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Acute Hepatopancreatic Necrosis Disease (AHPND): Virulence, Pathogenesis and Mitigation Strategies in Shrimp Aquaculture
Article

A Novel Glutathione S-Transferase Gtt2 Class (VpGSTT2) Is Found in the Genome of the AHPND/EMS Vibrio parahaemolyticus Shrimp Pathogen

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Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo 83304, Sonora, Mexico
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Departamento de Ciencias Químico-Biológicas, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico
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Departamento de Ciencias de la Salud, Universidad de Sonora, Cd. Obregón 85040, Sonora, Mexico
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Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico
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Departamento de Microbiología Molecular, Instituto de Biotecnología (IBt), Universidad Nacional Autónoma de Mexico (UNAM), Cuernavaca 62210, Morelos, Mexico
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Laboratorio de Genética Molecular de Plantas, Centro de Investigación en Alimentación y Desarrollo, A.C. (CIAD), Hermosillo 83304, Sonora, Mexico
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Department of Chemistry, The University of California, Davis, CA 95616, USA
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Consejo Nacional de Ciencia y Tecnología, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Colima 28629, Colima, Mexico
*
Authors to whom correspondence should be addressed.
Received: 3 July 2021 / Revised: 24 August 2021 / Accepted: 26 August 2021 / Published: 17 September 2021
Glutathione S-transferases are a family of detoxifying enzymes that catalyze the conjugation of reduced glutathione (GSH) with different xenobiotic compounds using either Ser, Tyr, or Cys as a primary catalytic residue. We identified a novel GST in the genome of the shrimp pathogen V. parahaemolyticus FIM- S1708+, a bacterial strain associated with Acute Hepatopancreatic Necrosis Disease (AHPND)/Early Mortality Syndrome (EMS) in cultured shrimp. This new GST class was named Gtt2. It has an atypical catalytic mechanism in which a water molecule instead of Ser, Tyr, or Cys activates the sulfhydryl group of GSH. The biochemical properties of Gtt2 from Vibrio parahaemolyticus (VpGSTT2) were characterized using kinetic and crystallographic methods. Recombinant VpGSTT2 was enzymatically active using GSH and CDNB as substrates, with a specific activity of 5.7 units/mg. Low affinity for substrates was demonstrated using both Michaelis–Menten kinetics and isothermal titration calorimetry. The crystal structure showed a canonical two-domain structure comprising a glutathione binding G-domain and a hydrophobic ligand H domain. A water molecule was hydrogen-bonded to residues Thr9 and Ser 11, as reported for the yeast Gtt2, suggesting a primary role in the reaction. Molecular docking showed that GSH could bind at the G-site in the vicinity of Ser11. G-site mutationsT9A and S11A were analyzed. S11A retained 30% activity, while T9A/S11A showed no detectable activity. VpGSTT2 was the first bacterial Gtt2 characterized, in which residues Ser11 and Thr9 coordinated a water molecule as part of a catalytic mechanism that was characteristic of yeast GTT2. The GTT2 family has been shown to provide protection against metal toxicity; in some cases, excess heavy metals appear in shrimp ponds presenting AHPND/EMS. Further studies may address whether GTT2 in V. parahaemolyticus pathogenic strains may provide a competitive advantage as a novel detoxification mechanism. View Full-Text
Keywords: glutathione s-transferase (GST); Vibrio parahaemolyticus; Gtt2 class; glutathione (GSH); kinetic isotope effect; crystal structure glutathione s-transferase (GST); Vibrio parahaemolyticus; Gtt2 class; glutathione (GSH); kinetic isotope effect; crystal structure
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MDPI and ACS Style

Valenzuela-Chavira, I.; Corona-Martinez, D.O.; Garcia-Orozco, K.D.; Beltran-Torres, M.; Sanchez-Lopez, F.; Arvizu-Flores, A.A.; Sugich-Miranda, R.; Lopez-Zavala, A.A.; Robles-Zepeda, R.E.; Islas-Osuna, M.A.; Ochoa-Leyva, A.; Toney, M.D.; Serrano-Posada, H.; Sotelo-Mundo, R.R. A Novel Glutathione S-Transferase Gtt2 Class (VpGSTT2) Is Found in the Genome of the AHPND/EMS Vibrio parahaemolyticus Shrimp Pathogen. Toxins 2021, 13, 664. https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13090664

AMA Style

Valenzuela-Chavira I, Corona-Martinez DO, Garcia-Orozco KD, Beltran-Torres M, Sanchez-Lopez F, Arvizu-Flores AA, Sugich-Miranda R, Lopez-Zavala AA, Robles-Zepeda RE, Islas-Osuna MA, Ochoa-Leyva A, Toney MD, Serrano-Posada H, Sotelo-Mundo RR. A Novel Glutathione S-Transferase Gtt2 Class (VpGSTT2) Is Found in the Genome of the AHPND/EMS Vibrio parahaemolyticus Shrimp Pathogen. Toxins. 2021; 13(9):664. https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13090664

Chicago/Turabian Style

Valenzuela-Chavira, Ignacio, David O. Corona-Martinez, Karina D. Garcia-Orozco, Melissa Beltran-Torres, Filiberto Sanchez-Lopez, Aldo A. Arvizu-Flores, Rocio Sugich-Miranda, Alonso A. Lopez-Zavala, Ramon E. Robles-Zepeda, Maria A. Islas-Osuna, Adrian Ochoa-Leyva, Michael D. Toney, Hugo Serrano-Posada, and Rogerio R. Sotelo-Mundo 2021. "A Novel Glutathione S-Transferase Gtt2 Class (VpGSTT2) Is Found in the Genome of the AHPND/EMS Vibrio parahaemolyticus Shrimp Pathogen" Toxins 13, no. 9: 664. https://0-doi-org.brum.beds.ac.uk/10.3390/toxins13090664

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