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Peptides: Molecular and Biotechnological Aspects
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Peptides: Molecular and Biotechnological Aspects

A special issue of Biomolecules (ISSN 2218-273X). This special issue belongs to the section "Cellular Biochemistry".

Deadline for manuscript submissions: closed (31 March 2020) | Viewed by 53302

Special Issue Editor

Dr. Hamilton Cabral

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Guest Editor
Associate Professor, School of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, CEP, Ribeirao Preto 14040-903, SP, Brazil
Interests: bioactive peptides; cancer; natural peptides; molecular biology; proteases and proteomic
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

According to the World Health Organization, thousands of deaths are related to an unhealthy diet that stands as one of the main risk factors for non-communicable diseases, also known as chronic diseases. Among these disorders, the most diffuse are cardiovascular diseases and cancers, which bear the major responsibility for mortality and morbidity. The increased incidence of these diseases leads to investigate new therapies. Peptides have been emerging as an alternative treatment for many disorders. They can interact with a specific target, eliciting a physiological effect. This specificity causes less side effects and lower toxicity and confers excellent safety, tolerability, and efficacy in humans.

On the other hand, these peptides have intrinsic weaknesses, with poor chemical and physical stability and short circulating plasma life. Many studies have been performed to design new drugs based on peptides, trying to minimize their disadvantages and improve their pharmacokinetic and pharmacodynamic characteristics. Despite numerous studies, the action mechanism of most peptides is not well known and necessitates further research.

The market of pharmaceutical peptides has been increasing proportionally to the number of researches, with a projected annual growth rate of 9–10%. In 2019, $70 billion of these medicines are expected to be sold, more than the amount predicted for pharmaceuticals worldwide.

Assoc. Prof. Hamilton Cabral
Guest Editor

Manuscript Submission Information

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Keywords

  • chronic diseases
  • natural peptide
  • mechanism of action
  • peptide delivery
  • peptide design
  • peptide-protein interaction
  • pharmaceutical peptide
  • synthetic peptide
  • biological activity of peptides
  • peptide developments and peptide stability

Published Papers (15 papers)

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Editorial

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3 pages, 175 KiB  
Editorial
Peptides: Molecular and Biotechnological Aspects
by Hamilton Cabral
Biomolecules 2021, 11(1), 52; https://doi.org/10.3390/biom11010052 - 01 Jan 2021
Cited by 4 | Viewed by 1882
Abstract
Since the isolation and commercialization of insulin (a peptide composed of 51 amino acid residues) in the early 1920s, peptide drugs have reshaped the pharmaceutical industry [...] Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)

Research

Jump to: Editorial

17 pages, 2306 KiB  
Article
Development and Characterization of a Novel Peptide-Loaded Antimicrobial Ocular Insert
by Eleonora Terreni, Susi Burgalassi, Patrizia Chetoni, Silvia Tampucci, Erica Zucchetti, Roberta Fais, Emilia Ghelardi, Antonella Lupetti and Daniela Monti
Biomolecules 2020, 10(5), 664; https://0-doi-org.brum.beds.ac.uk/10.3390/biom10050664 - 25 Apr 2020
Cited by 14 | Viewed by 2661
Abstract
Infectious ocular keratitis is the leading cause of blindness worldwide. Bacterial resistance to classical pharmacological treatments raised the interest of researchers towards antimicrobial peptide (AMP)-based therapy. hLF 1-11, a synthetic antimicrobial peptide derived from the N-terminus of human lactoferrin, proved effective against different [...] Read more.
Infectious ocular keratitis is the leading cause of blindness worldwide. Bacterial resistance to classical pharmacological treatments raised the interest of researchers towards antimicrobial peptide (AMP)-based therapy. hLF 1-11, a synthetic antimicrobial peptide derived from the N-terminus of human lactoferrin, proved effective against different bacteria and yeast but, like all proteinaceous materials, it is unstable from chemical, physical, and biological points of view. In this study, new freeze-dried solid matrices containing mucoadhesive polymers were prepared and characterized in terms of rheology, hydration time, bioadhesion, drug content, and in vitro release. The formulation HPMC/T2/HA/hLF 1-11fd was selected for the delivery of hLF 1-11, since it showed good drug recovery and no chemical degradation up to at least 6 months (long-term stability). Furthermore, the HPMC/T2/HA/hLF 1-11fd matrix allowed for the release of the drug in a simulated physiological environment, linked to an optimal hydration time, and the peptide antimicrobial activity was preserved for up to 15 months of storage, a very promising result considering the chemical liability of proteinaceous material. For its properties, the freeze-dried matrix developed in this study could be a good platform for the delivery of antimicrobial peptides in the precorneal area to treat infectious phenomena of the ocular surface. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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19 pages, 2030 KiB  
Article
Exogenous Ghrelin Increases Plasma Insulin Level in Diabetic Rats
by Haba Elabadlah, Rasheed Hameed, Crystal D’Souza, Sahar Mohsin and Ernest A. Adeghate
Biomolecules 2020, 10(4), 633; https://0-doi-org.brum.beds.ac.uk/10.3390/biom10040633 - 19 Apr 2020
Cited by 15 | Viewed by 4356
Abstract
Ghrelin, a 28-amino acid peptide, is a strong growth hormone secretagogue and a regulator of food intake. In addition, ghrelin is thought to play a role in insulin secretion and in glucose homeostasis. A lot of contradictory data have been reported in the [...] Read more.
Ghrelin, a 28-amino acid peptide, is a strong growth hormone secretagogue and a regulator of food intake. In addition, ghrelin is thought to play a role in insulin secretion and in glucose homeostasis. A lot of contradictory data have been reported in the literature regarding the co-localization of ghrelin with other hormones in the islet of Langerhans, its role in insulin secretion and attenuation of type 2 diabetes mellitus. In this study, we investigate the effect of chronic ghrelin treatment on glucose, body weight and insulin level in normal and streptozotocin-induced diabetic male Wistar rats. We have also examined the distribution pattern and co-localization of ghrelin with insulin in pancreatic islet cells using immunohistochemistry and immune-electron microscopy and the ability of ghrelin to stimulate insulin release from the CRL11065 beta cell line. Control, non-diabetic groups received intraperitoneal injection of normal saline, while treated groups received intraperitoneal injection of 5 µg/kg body weight of ghrelin (amino acid chain 24–51) on a daily basis for a duration of four weeks. Our results show that the administration of ghrelin increases the number of insulin-secreting beta cells and serum insulin level in both normal and diabetic rats. We also demonstrated that ghrelin co-localizes with insulin in pancreatic islet cells and that the pattern of ghrelin distribution is altered after the onset of diabetes. Moreover, ghrelin at a dose of 10−6 M and 10−12 M increased insulin release from the CRL11065 beta cell line. In summary, ghrelin co-localizes with insulin in the secretory granules of pancreatic beta cells and enhances insulin production. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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19 pages, 3081 KiB  
Article
Camel Hemorphins Exhibit a More Potent Angiotensin-I Converting Enzyme Inhibitory Activity than Other Mammalian Hemorphins: An In Silico and In Vitro Study
by Amanat Ali, Seham Abdullah Rashed Alzeyoudi, Shamma Abdulla Almutawa, Alya Nasir Alnajjar, Yusra Al Dhaheri and Ranjit Vijayan
Biomolecules 2020, 10(3), 486; https://0-doi-org.brum.beds.ac.uk/10.3390/biom10030486 - 23 Mar 2020
Cited by 11 | Viewed by 4022
Abstract
Angiotensin-I converting enzyme (ACE) is a zinc metallopeptidase that has an important role in regulating the renin-angiotensin-aldosterone system (RAAS). It is also an important drug target for the management of cardiovascular diseases. Hemorphins are endogenous peptides that are produced by proteolytic cleavage of [...] Read more.
Angiotensin-I converting enzyme (ACE) is a zinc metallopeptidase that has an important role in regulating the renin-angiotensin-aldosterone system (RAAS). It is also an important drug target for the management of cardiovascular diseases. Hemorphins are endogenous peptides that are produced by proteolytic cleavage of beta hemoglobin. A number of studies have reported various therapeutic activities of hemorphins. Previous reports have shown antihypertensive action of hemorphins via the inhibition of ACE. The sequence of hemorphins is highly conserved among mammals, except in camels, which harbors a unique Q>R variation in the peptide. Here, we studied the ACE inhibitory activity of camel hemorphins (LVVYPWTRRF and YPWTRRF) and non-camel hemorphins (LVVYPWTQRF and YPWTQRF). Computational methods were used to determine the most likely binding pose and binding affinity of both camel and non-camel hemorphins within the active site of ACE. Molecular dynamics simulations showed that the peptides interacted with critical residues in the active site of ACE. Notably, camel hemorphins showed higher binding affinity and sustained interactions with all three subsites of the ACE active site. An in vitro ACE inhibition assay showed that the IC50 of camel hemorphins were significantly lower than the IC50 of non-camel hemorphins. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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16 pages, 5005 KiB  
Article
Hemoglobin Reassembly of Antimicrobial Fragments from the Midgut of Triatoma infestans
by Laura Cristina Lima Diniz and Pedro Ismael da Silva Junior
Biomolecules 2020, 10(2), 261; https://0-doi-org.brum.beds.ac.uk/10.3390/biom10020261 - 10 Feb 2020
Cited by 1 | Viewed by 2537
Abstract
Hemoglobin is one of the most important molecules of the human body. Beyond its physiological activity, hemoglobins are able to inhibit the growth of several microorganisms. Since 1999, studies have reported that antimicrobial peptides can be produced by blood-feeding insects through hemoglobin digestion, [...] Read more.
Hemoglobin is one of the most important molecules of the human body. Beyond its physiological activity, hemoglobins are able to inhibit the growth of several microorganisms. Since 1999, studies have reported that antimicrobial peptides can be produced by blood-feeding insects through hemoglobin digestion, and it has been reported that Triatoma infestans can generate an antimicrobial fragment from human fibrinopeptide. Thus T. infestans intestinal content was analyzed through Reverse Phase High-Performance Liquid Chromatography (RP-HPLC), the eluted fractions were tested against Micrococcus luteus, Escherichia coli and Staphylococcus aureus, and the active fractions submitted to mass spectrometry. The data obtained were compared to hemoglobin databases to verify the presence of hemoglobin-derived fragments. Ten fractions eluted from chromatography presented antimicrobial activity, and when analyzed through mass spectrometry revealed the presence of 8 murine hemoglobin α-chain fragments and 24 fragments from murine hemoglobin β fragments. Through the compilation of the fragments is possible to obtain over 67% coverage of both sequences. Part of the amino acid sequences corresponds to the sequences already identified on other intestinal contents of arthropods, and are highly conserved between the blood of other wild animals that are the most common intermediate hosts of Chagas’ disease in Brazil and some of the main natural blood source for triatomines. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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14 pages, 2076 KiB  
Article
Cell Penetrating Peptide as a High Safety Anti-Inflammation Ingredient for Cosmetic Applications
by Tse-Kai Fu, Ping-Hsueh Kuo, Yen-Chang Lu, Hsing-Ni Lin, Lily Hui-Ching Wang, Yu-Chun Lin, Yu-Chen Kao, Huey-Min Lai and Margaret Dah-Tsyr Chang
Biomolecules 2020, 10(1), 101; https://0-doi-org.brum.beds.ac.uk/10.3390/biom10010101 - 07 Jan 2020
Cited by 11 | Viewed by 4724
Abstract
Cosmeceutical peptides have become an important topic in recent decades in both academic and industrial fields. Many natural or synthetic peptides with different biological functions including anti-ageing, anti-oxidation, anti-infection and anti-pigmentation have been developed and commercialized. Current cosmeceutical peptides have already satisfied most [...] Read more.
Cosmeceutical peptides have become an important topic in recent decades in both academic and industrial fields. Many natural or synthetic peptides with different biological functions including anti-ageing, anti-oxidation, anti-infection and anti-pigmentation have been developed and commercialized. Current cosmeceutical peptides have already satisfied most market demand, remaining: “cargos carrying skin penetrating peptide with high safety” still an un-met need. To this aim, a cell-penetrating peptide, CPPAIF, which efficiently transported cargos into epithelial cells was exanimated. CPPAIF was evaluated with cell model and 3D skin model following OECD guidelines without using animal models. As a highly stable peptide, CPPAIF neither irritated nor sensitized skin, also did not disrupt skin barrier. In addition, such high safety peptide had anti-inflammation activity without allergic effect. Moreover, cargo carrying activity of CPPAIF was assayed using HaCaT cell model and rapid CPPAIF penetration was observed within 30 min. Finally, CPPAIF possessed transepidermal activity in water in oil formulation without disruption of skin barrier. All evidences indicated that CPPAIF was an ideal choice for skin penetrating and its anti-inflammatory activity could improve skin condition, which made CPPAIF suitable and attractive for novel cosmeceutical product development. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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15 pages, 2771 KiB  
Article
Elucidating the Binding Mechanism of a Novel Silica-Binding Peptide
by Rachit Bansal, Zehra Elgundi, Andrew Care, Sophia C. Goodchild, Megan S. Lord, Alison Rodger and Anwar Sunna
Biomolecules 2020, 10(1), 4; https://0-doi-org.brum.beds.ac.uk/10.3390/biom10010004 - 18 Dec 2019
Cited by 5 | Viewed by 3547
Abstract
Linker-protein G (LPG) is a bifunctional fusion protein composed of a solid-binding peptide (SBP, referred as the “linker”) with high affinity to silica-based compounds and a Streptococcus protein G (PG), which binds antibodies. The binding mechanisms of LPG to silica-based materials was studied [...] Read more.
Linker-protein G (LPG) is a bifunctional fusion protein composed of a solid-binding peptide (SBP, referred as the “linker”) with high affinity to silica-based compounds and a Streptococcus protein G (PG), which binds antibodies. The binding mechanisms of LPG to silica-based materials was studied using different biophysical techniques and compared to that of PG without the linker. LPG displayed high binding affinity to a silica surface (KD = 34.77 ± 11.8 nM), with a vertical orientation, in comparison to parent PG, which exhibited no measurable binding affinity. Incorporation of the linker in the fusion protein, LPG, had no effect on the antibody-binding function of PG, which retained its secondary structure and displayed no alteration of its chemical stability. The LPG system provided a milder, easier, and faster affinity-driven immobilization of antibodies to inorganic surfaces when compared to traditional chemical coupling techniques. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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20 pages, 3145 KiB  
Article
Unravelling the Skin Secretion Peptides of the Gliding Leaf Frog, Agalychnis spurrelli (Hylidae)
by Carolina Proaño-Bolaños, Ailín Blasco-Zúñiga, José Rafael Almeida, Lei Wang, Miguel Angel Llumiquinga, Miryan Rivera, Mei Zhou, Tianbao Chen and Chris Shaw
Biomolecules 2019, 9(11), 667; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9110667 - 30 Oct 2019
Cited by 11 | Viewed by 6250
Abstract
Frog skin secretions contain medically-valuable molecules, which are useful for the discovery of new biopharmaceuticals. The peptide profile of the skin secretion of Agalychnis spurrelli has not been investigated; therefore, the structural and biological characterization of its compounds signify an inestimable opportunity to [...] Read more.
Frog skin secretions contain medically-valuable molecules, which are useful for the discovery of new biopharmaceuticals. The peptide profile of the skin secretion of Agalychnis spurrelli has not been investigated; therefore, the structural and biological characterization of its compounds signify an inestimable opportunity to acquire new biologically-active chemical scaffolds. In this work, skin secretion from this amphibian was analysed by molecular cloning and tandem mass spectrometry. Although the extent of this work was not exhaustive, eleven skin secretion peptides belonging to five peptide families were identified. Among these, we report the occurrence of two phyllokinins, and one medusin-SP which were previously reported in other related species. In addition, eight novel peptides were identified, including four dermaseptins, DRS-SP2 to DRS-SP5, one phylloseptin-SP1, and three orphan peptides. Phylloseptin-SP1 and dermaseptins-SP2 were identified in HPLC fractions based on their molecular masses determined by MALDI-TOF MS. Among the antimicrobial peptides, dermaseptin-SP2 was the most potent, inhibiting Escherichia coli, Staphylococcus aureus, and ORSA with a minimum inhibitory concentration (MIC) of 2.68 μM, and Candida albicans with an MIC of 10.71 μM, without haemolytic effects. The peptides described in this study represent but a superficial glance at the considerable structural diversity of bioactive peptides produced in the skin secretion of A. spurrelli. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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14 pages, 2240 KiB  
Article
Design of N-Terminal Derivatives from a Novel Dermaseptin Exhibiting Broad-Spectrum Antimicrobial Activity against Isolates from Cystic Fibrosis Patients
by Yuan Ying, Hui Wang, Xinping Xi, Chengbang Ma, Yue Liu, Mei Zhou, Qiang Du, James F. Burrows, Minjie Wei, Tianbao Chen and Lei Wang
Biomolecules 2019, 9(11), 646; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9110646 - 24 Oct 2019
Cited by 12 | Viewed by 2615
Abstract
Dermaseptins are an antimicrobial peptide family widely identified from the skin secretions of phyllomeudusinae frogs. Here, we identify Dermaseptin-PC (DM-PC), from the skin secretion of Phyllomedusa coelestis, and further investigate the properties of this peptide, and a number of rationally designed truncated [...] Read more.
Dermaseptins are an antimicrobial peptide family widely identified from the skin secretions of phyllomeudusinae frogs. Here, we identify Dermaseptin-PC (DM-PC), from the skin secretion of Phyllomedusa coelestis, and further investigate the properties of this peptide, and a number of rationally designed truncated derivatives. The truncated 19-mer derived from the N-terminus exhibited similar antimicrobial potency when compared to the parent peptide, but the haemolytic effect of this truncated peptide was significantly decreased. Based on previous studies, the charge and hydrophobicity of truncated derivatives can affect the bioactivity of these peptides and thus we designed a 10-mer derivative with an optimised positive charge and a cyclohexylalanine (Cha) at the C-terminus for enhancing the hydrophobicity, DMPC-10A, which retained the antimicrobial activity of the parent peptide. To further investigate the influence of Cha at the C-terminus on activity, it was substituted by alanine (Ala) to generate another derivative, DMPC-10, but this was found to be much less potent. In addition, DM-PC, DMPC-19 and DMPC-10A not only rapidly killed planktonic bacteria isolated from cystic fibrosis (CF) patient, but also effectively eradicated their biofilm matrices. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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12 pages, 2326 KiB  
Article
Electro-Acupuncture Alleviates Cisplatin-Induced Anorexia in Rats by Modulating Ghrelin and Monoamine Neurotransmitters
by Ji Yun Baek, Tuy An Trinh, Wonsang Huh, Ji Hoon Song, Hyun Young Kim, Juhee Lim, Jinhee Kim, Hyun Jin Choi, Tae-Hun Kim and Ki Sung Kang
Biomolecules 2019, 9(10), 624; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9100624 - 18 Oct 2019
Cited by 14 | Viewed by 3340
Abstract
Anorexia is common in patients with cancer, mostly as a side effect of chemotherapy. The effect of electro-acupuncture (EA) on ameliorating cancer-related symptoms have been studied in animal models and in clinical trials. The aim of this study was to determine optimal conditions [...] Read more.
Anorexia is common in patients with cancer, mostly as a side effect of chemotherapy. The effect of electro-acupuncture (EA) on ameliorating cancer-related symptoms have been studied in animal models and in clinical trials. The aim of this study was to determine optimal conditions for the application of EA to alleviate anorexia, followed by the study of molecular mechanisms affecting its therapeutics. Anorexia was induced in male Wistar rats by injecting cisplatin, which was then followed by EA treatment at CV12, the acupuncture point located in the center of the abdominal midline. Body weight and food intake were measured daily throughout the duration of the study. The levels of monoamine neurotransmitters in the plasma were quantitatively analyzed by HPLC-ECD. Gastrointestinal hormone concentrations were elucidated with ELISA kits. RT-qPCR was performed to evaluate the mRNA expression of ghrelin (GHRL), neuropeptide Y (NPY), and pro-opiomelanocortin. The expression of c-Fos in the nucleus tractus solitarii was detected using western blotting analysis. The optimal conditions of EA to alleviate anorexia in rats was determined to be 1 unit for intensity and 10 Hz for frequency. EA treatment at CV12 reduced the levels of plasma monoamine neurotransmitters 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, dopamine, and norepinephrine; as well as stimulated the expression of GHRL and NPY to alleviate cisplatin-induced anorexia in rats. EA stimulation at CV12 could be used to treat cisplatin-induced anorexia in rats. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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15 pages, 885 KiB  
Article
Effect of Marination Time on the Antioxidant Properties of Peptides Extracted from Organic Dry-Fermented Beef
by Paulina Kęska, Karolina M. Wójciak and Joanna Stadnik
Biomolecules 2019, 9(10), 614; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9100614 - 16 Oct 2019
Cited by 6 | Viewed by 2642
Abstract
In this study, we evaluated the effect of marination time on changes in the antioxidant properties of peptides extracted from bovine semimembranosus muscle. We measured antiradical scavenging capacity and reducing power of the peptides using a spectrophotometric decolorization method; inhibition of lipid oxidation [...] Read more.
In this study, we evaluated the effect of marination time on changes in the antioxidant properties of peptides extracted from bovine semimembranosus muscle. We measured antiradical scavenging capacity and reducing power of the peptides using a spectrophotometric decolorization method; inhibition of lipid oxidation was also assessed by estimating the level of malondialdehyde formed. According to our results, there was no benefit from the doubling of marinating time (from 24 to 48 h) as part of the preprocessing of beef. Samples from S1 batch (24 h marination) showed better antioxidant properties than those from S2 batch. We also tested various color parameters as a reflection of the inhibition of oxidative processes, in which case, the most favorable parameters from the consumer point of view were found to be lightness and redness. The effect of marination time on the degree of proteolytic changes was estimated using peptidomic approach. The degradation of myoglobin, hemoglobin, creatine kinase-type M, and beta-enolase—as the most sensitive proteins to proteolytic degradation—was observed during the 62 days of processing. It seems that the prolongation of marination time as a preprocessing step intensifies the hydrolytic degradation of proteins and peptides during the processing step. This results in the loss (or it has no effect) of antioxidative properties in organic dry-fermented beef. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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15 pages, 4605 KiB  
Article
Cooperative Cellular Uptake and Activity of Octaarginine Antisense Peptide Nucleic Acid (PNA) Conjugates
by Mahdi Ghavami, Takehiko Shiraishi and Peter E. Nielsen
Biomolecules 2019, 9(10), 554; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9100554 - 01 Oct 2019
Cited by 17 | Viewed by 3237
Abstract
Cellular uptake and antisense activity of d-octaarginine conjugated peptide nucleic acids (PNAs) is shown to exhibit pronounced cooperativity in serum-containing medium, in particular by being enhanced by analogous mis-match PNA–cell-penetrating peptide (PNA–CPP) conjugates without inherent antisense activity. This cooperativity does not show [...] Read more.
Cellular uptake and antisense activity of d-octaarginine conjugated peptide nucleic acids (PNAs) is shown to exhibit pronounced cooperativity in serum-containing medium, in particular by being enhanced by analogous mis-match PNA–cell-penetrating peptide (PNA–CPP) conjugates without inherent antisense activity. This cooperativity does not show cell or PNA sequence dependency, suggesting that it is a common effect in cationic CPP conjugated PNA delivery. Interestingly, our results also indicate that Deca-r8-PNA and r8-PNA could assist each other and even other non-CPP PNAs as an uptake enhancer agent. However, the peptide itself (without being attached to the PNA) failed to enhance uptake and antisense activity. These results are compatible with an endosomal uptake mechanism in which the endocytosis event is induced by multiple CPP–PNA binding to the cell surface requiring a certain CPP density, possibly in terms of nanoparticle number and/or size, to be triggered. In particular the finding that the number of endosomal events is dependent on the total CPP–PNA concentration supports such a model. It is not possible from the present results to conclude whether endosomal escape is also cooperatively induced by CPP–PNA. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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16 pages, 4651 KiB  
Article
Studies on the Interaction of Alyteserin 1c Peptide and Its Cationic Analogue with Model Membranes Imitating Mammalian and Bacterial Membranes
by Alberto Aragón-Muriel, Alessio Ausili, Kevin Sánchez, Oscar E. Rojas A., Juan Londoño Mosquera, Dorian Polo-Cerón and Jose Oñate-Garzón
Biomolecules 2019, 9(10), 527; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9100527 - 25 Sep 2019
Cited by 11 | Viewed by 3023
Abstract
Antimicrobial peptides (AMPs) are effector molecules of the innate immune system and have been isolated from multiple organisms. Their antimicrobial properties are due to the fact that they interact mainly with the anionic membrane of the microorganisms, permeabilizing it and releasing the cytoplasmic [...] Read more.
Antimicrobial peptides (AMPs) are effector molecules of the innate immune system and have been isolated from multiple organisms. Their antimicrobial properties are due to the fact that they interact mainly with the anionic membrane of the microorganisms, permeabilizing it and releasing the cytoplasmic content. Alyteserin 1c (+2), an AMP isolated from Alytes obstetricans and its more cationic and hydrophilic analogue (+5) were synthesized using the solid phase method, in order to study the interaction with model membranes by calorimetric and spectroscopic assays. Differential scanning calorimetry (DSC) showed that both peptides had a strong effect when the membrane contained phosphatidylcholine (PC) alone or was mixed with phosphatidylglycerol (PG), increasing membrane fluidization. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used to study the secondary structure of the peptide. Peptide +2 exhibited a transition from β-sheet/turns to β-sheet/α-helix structures after binding with model membranes, whereas peptide +5 had a transition from aggregation/unordered to β-sheet/α-helix structures after binding with membrane-contained PC. Interestingly, the latter showed a β-sheet structure predominantly in the presence of PG lipids. Additionally, molecular dynamics (MD) results showed that the carboxy-terminal of the peptide +5 has the ability to insert into the surface of the PC/PG membranes, resulting in the increase of the membrane fluidity. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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15 pages, 5349 KiB  
Article
Bioevaluation of Ranatuerin-2Pb from the Frog Skin Secretion of Rana pipiens and Its Truncated Analogues
by Xiaowei Zhou, Daning Shi, Ruimin Zhong, Zhuming Ye, Chengbang Ma, Mei Zhou, Xinping Xi, Lei Wang, Tianbao Chen and Hang Fai Kwok
Biomolecules 2019, 9(6), 249; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9060249 - 25 Jun 2019
Cited by 19 | Viewed by 3330
Abstract
Antimicrobial peptides (AMPs) are considered as a promising agent to overcome the drug-resistance of bacteria. Large numbers of AMPs have been identified from the skin secretion of Rana pipiens, including brevinins, ranatuerins, temporins and esculentins. In this study, the cDNA precursor of [...] Read more.
Antimicrobial peptides (AMPs) are considered as a promising agent to overcome the drug-resistance of bacteria. Large numbers of AMPs have been identified from the skin secretion of Rana pipiens, including brevinins, ranatuerins, temporins and esculentins. In this study, the cDNA precursor of a broad-spectrum antimicrobial peptide, ranatuerin-2Pb, was cloned and identified. Additionally, two truncated analogues, RPa and RPb, were synthesised to investigate the structure-activity relationship of ranatuerin-2Pb. RPa lost antimicrobial activity against Candida albicans, MRSA, Enterococcus faecalis and Pseudomonas aeruginosa, while RPb retained its broad-spectrum antimicrobial activity. Additionally, ranatuerin-2Pb, RPa and RPb demonstrated inhibition and eradication effects against Staphylococcus aureus biofilm. RPb showed a rapid bacterial killing manner via membrane permeabilization without damaging the cell membrane of erythrocytes. Moreover, RPb decreased the mortality of S. aureus infected Galleria mellonella larvae. Collectively, our results suggested that RPb may pave a novel way for natural antimicrobial drug design. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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13 pages, 2964 KiB  
Article
LFB: A Novel Antimicrobial Brevinin-Like Peptide from the Skin Secretion of the Fujian Large Headed Frog, Limnonectes fujianensi
by Bin Li, Peng Lyu, Shuping Xie, Haixin Qin, Wenyuan Pu, Houxi Xu, Tianbao Chen, Chris Shaw, Lilin Ge and Hang Fai Kwok
Biomolecules 2019, 9(6), 242; https://0-doi-org.brum.beds.ac.uk/10.3390/biom9060242 - 21 Jun 2019
Cited by 19 | Viewed by 4083
Abstract
Amphibians are a natural source of abundant antimicrobial peptides and thus have been widely investigated for isolation of such biomolecules. Many new antimicrobial peptide families have been discovered from amphibians. In this study, a novel antimicrobial peptide named Limnonectes fujianensis Brevinvin (LFB) has [...] Read more.
Amphibians are a natural source of abundant antimicrobial peptides and thus have been widely investigated for isolation of such biomolecules. Many new antimicrobial peptide families have been discovered from amphibians. In this study, a novel antimicrobial peptide named Limnonectes fujianensis Brevinvin (LFB) has been identified in the skin secretion from the Fujian large headed frog, Limnonectes fujianensis. The cDNA sequence was cloned from a skin secretion library and the predicted mature peptide was identified through MS/MS fragmentation sequencing of reverse phase HPLC fractions on the same sample. LFB was predicted to be an amphipathic, hydrophobic, alpha helical, and beta turn peptide that inserts into a lipid bilayer in order to kill the cells. In antimicrobial assays, a synthetic replicate of this novel antimicrobial peptide demonstrated significant activity against the Gram-positive bacterium Staphylococcus aureus, the Gram-negative bacterium Escherichia coli and the yeast, Candida albicans. This novel peptide was highly potent (MIC 4.88 uM) against Gram-negative bacterium, and also has the ability to inhibit the growth of human cancer cell lines with IC50 values ranging from 18.9 μM down to 2.0 μM. These findings help to enrich our understanding of Brevinin-like peptides. Moreover, the data presented here validate frog secretion as a source of potential novel antimicrobial peptides, that also exhibit anti-tumor properties, that could be useful for the treatment of cancer. Full article
(This article belongs to the Special Issue Peptides: Molecular and Biotechnological Aspects)
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