title: Analysis of the isomerase and chaperone-like activities of an amebic PDI (EhPDI).
abstract: Protein disulfide isomerases (PDI) are eukaryotic oxidoreductases that catalyze the formation and rearrangement of disulfide bonds during folding of substrate proteins. Structurally, PDI enzymes share as a common feature the presence of at least one active thioredoxin-like domain. PDI enzymes are also involved in holding, refolding, and degradation of unfolded or misfolded proteins during stressful conditions. The EhPDI enzyme (a 38 kDa polypeptide with two active thioredoxin-like domains) has been used as a model to gain insights into protein folding and disulfide bond formation in E. histolytica. Here, we performed a functional complementation assay, using a ΔdsbC mutant of E. coli, to test whether EhPDI exhibits isomerase activity in vivo. Our preliminary results showed that EhPDI exhibits isomerase activity; however, further mutagenic analysis revealed significant differences in the functional role of each thioredoxin-like domain. Additional studies confirmed that EhPDI protects heat-labile enzymes against thermal inactivation, extending our knowledge about its chaperone-like activity. The characterization of EhPDI, as an oxidative folding catalyst with chaperone-like function, represents the initial step to dissect the molecular mechanisms involved in protein folding in E. histolytica.
authors.affiliation: Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Calzada Universidad 14418, Parque Industrial Internacional, 22390 Tijuana, BCN, Mexico.
authors.forename: Rosa E
authors.identifier: 0000-0001-6102-6966
authors.initials: RE
authors.lastname: Mares
authors.affiliation: Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Calzada Universidad 14418, Parque Industrial Internacional, 22390 Tijuana, BCN, Mexico.
authors.forename: Alexis Z
authors.identifier: 0000-0001-6024-9690
authors.initials: AZ
authors.lastname: Minchaca
authors.affiliation: Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Calzada Universidad 14418, Parque Industrial Internacional, 22390 Tijuana, BCN, Mexico.
authors.forename: Salvador
authors.identifier: 0000-0001-6940-5258
authors.initials: S
authors.lastname: Villagrana
authors.affiliation: Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Calzada Universidad 14418, Parque Industrial Internacional, 22390 Tijuana, BCN, Mexico.
authors.forename: Samuel G
authors.initials: SG
authors.lastname: Meléndez-López
authors.affiliation: Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Calzada Universidad 14418, Parque Industrial Internacional, 22390 Tijuana, BCN, Mexico.
authors.forename: Marco A
authors.identifier: 0000-0002-8950-2079
authors.initials: MA
authors.lastname: Ramos
mesh_terms: D002384:Catalysis; D004748:Entamoeba histolytica / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D017510:Protein Folding; D017434:Protein Structure, Tertiary / Q000502:physiology; D013879:Thioredoxins / Q000378:metabolism
chemical_list: D018832:Molecular Chaperones; D013879:Thioredoxins; D010088:Oxidoreductases; D019704:Protein Disulfide-Isomerases