Dr. Mendoza is interested in elucidating structure-function relationships of the "stress proteins", GroEL from E.coli, mammalian alpha-crystallin and Hsp60 from H.pylori.  These proteins, also referred to as molecular chaperones, protect cells from the adverse effects of stressful conditions (i.e. heat, oxidation, acid, etc.).  Recently, he has initiated studies of potential protective effects of stress-sensitive enzymes by a combination of GroEL and osmolytes which are small organic molecules that accumulmate during cellular stress.  This research involves a combination of biochemical assays and fluorescence measurements of model enzymes.

B.S. Chemistry, Instituto Tecnologico y de Estudios Superiores de Monterrey (Mexico), 1974

M.S. Chemistry, University of Texas at El Paso, 1982

Ph.D. Biochemistry, University of Texas Health Science Center at San Antonio, 1992

Postdoctoral work at the University of Utah and University of Texas Health Science Center at San Antonio, 1992-1994

Mendoza, J.A., Ignacio, J.L., and Buckley, C.M. (2021) The Hsp60 Protein of Helicobacter Pylory Exhibits Chaperone and ATPase Activities at Elevated Temperatures. BioChem 1, 19-25.

Mendoza, J.A., Weinberger, K.K., and Swan, M.J. (2017) The Hsp60 protein of helicobacter pylori displays chaperone activity under acidic conditions. Biochem.Biophys.Rep. 9, 95-99.

Mendoza, J.A., Correa, M.D., and Zardeneta, G. (2012) GTP binds to alpha-crystallin and causes a significant conformational change. Int.J.Biol.Macromol. 50, 895-898.

Melkani, G.C., Sielaff, R., Zardeneta, G., and Mendoza, J.A. (2012) Interaction of oxidized chaperonin GroEL with an unfolded protein at low temperatures. Biosci.Rep. 32, 299-303.

Melkani, G.C., Sielaff, R.L., Zardeneta, G., and Mendoza, J.A. (2008) Divalent cations stabilize GroEL under conditions of oxidative stress. Biochem.Biophys.Res.Commun. 368, 625-630.

Melkani, G.C., Kestetter, J., Sielaff, R., Zardeneta, G., and Mendoza, J.A. (2006) Protection of GroEL by its methionine residues against oxidation by hydrogen peroxide. Biochem.Biophys.Res.Commun. 347, 534-539.

Melkani, G.C., Zardeneta, G., and Mendoza, J.A. (2005) On the Chaperonin Activity of GroEL at Heat-Shock Temperature. Int.J.Biochem.Cell Biol. 37, 1375-138

Melkani, G.C., McNamara, C., Zardeneta, G., and Mendoza, J.A. (2004) Hydrogen Peroxide Induces the Dissociation of GroEL into Monomers that Can Facilitate the Reactivation of Oxidatively Inactivated Rhodanese. Int.J.Biochem.Cell Biol. 36, 505-518

Melkani, G.C., Zardeneta, G., and Mendoza, J.A. (2004) Oxidized GroEL Can Function as a Chaperonin. Frontiers Biosc. 9, 724-731

Melkani, G.C., Zardeneta, G., and Mendoza, J.A. (2003) The ATPase Activity of GroEL Is Supported at High Temperatures by Divalent Cations that Stabilize its Structure. Biometals. 16, 479-484

Melkani, G.C., Zardeneta, G., and Mendoza, J.A. (2002) GroEL Interacts Transiently with Oxidatively Inactivated Rhodanese Facilitating its Reactivation. Biochem.Biophys.Res.Commun. 294, 893-899

Del Fierro, D., Zardeneta, G., and Mendoza, J.A. (2000) Alpha-Crystallin Facilitates the Reactivation of Hydrogen Peroxide-Inactivated Rhodanese. Biochem.Biophys.Res.Commun. 274, 461-466

Mendoza, J.A., Dulin,P., and Warren,T. (2000) The Lower Hydrolysis of ATP by the Stress Protein GroEL Is a Major Factor Responsible for the Diminished Chaperonin Activity at Low Temperature. Cryobiology. 41, 319-323

Mendoza, J.A., Warren T, and Dulin, P. (1996) The ATPase Activity of Chaperonin GroEL Is Highly Stimulated at Elevated Temperatures. Biochem.Biophys.Res.Commun. 229, 271-274

Mendoza, J.A., Wilson, M., Joves, F., and Ackermann, E. (1996) Thermostabilization of Enzymes by the Chaperonin GroEL. Biotech.Techniques. 7, 535-540

Mendoza, J.A., and Del Campo, G. (1996) Ligand-induced Conformational Changes of GroEL Are Dependent on the Bound Substrate Polypeptide. J.Biol.Chem. 271, 16344-16349

Mendoza, J.A., Martinez, J.L., and Horowitz, P.M. (1995) Tetradecameric-cpn60 Can Be Reassembled In Vitro from Monomers in a Process that Is ATP Independent and Influenced by Cpn10. Biochim.Biophys.Acta. 1247, 209-214 

Mendoza, J.A., and Horowitz, P.M. (1994) Bound Substrate Polypeptides Can Generally Stabilize the Tetradecameric Structure of Cpn60 and induce Its Reassembly from Monomers. J.Biol.Chem. 269, 25963-25965.

Mendoza, J.A., Demeler, B., and Horowitz,P.M. (1994) Alteration of the Quaternary Structure of Cpn60 Modulates Chaperonin Assisted Folding: Implications for the Mechanism of Chaperonin Action. J.Biol.Chem. 269, 2447-2451.

Mendoza, J.A., and Horowitz, P.M. (1994) The Chaperonin Assisted and Unassisted Refolding of Rhodanese Can Be Modulated by Its N-terminal Peptide. J.Protein Chem. 13, 15-22.

Goldenberg, D.P., Mendoza,J.A., and Zhang, J-X. (1994) Mutational Analysis of the BPTI Folding Pathway. Methods in Prot.Struct.Anal. 44, 483-492.

Mendoza, J.A., Jarsfter, M.B., and Goldenberg, D.P. (1994) Effects of Amino Acid Replacements on the Reductive Unfolding Kinetics of Pancreatic Trypsin Inhibitor. Biochemistry. 33, 1143-1148.

Mendoza, J.A., Grant,E., and Horowitz, P.M. (1993) Partially Folded Rhodanese or Its N-terminal Peptide Can Disrupt Phospholipid Vesicles. J.Protein Chem. 12, 65-69.

Mendoza, J.A., and Horowitz, P.M. (1992) Sulfhydryl Modification of E.coli Cpn60 Leads to Loss of Its Ability to Support Refolding of Rhodanese but not to Form a Binary Complex. J.Protein Chem. 11, 589-594.

Mendoza, J.A., Lorimer, G.H., and Horowitz, P.M. (1992) Chaperonin Cpn60 from E.coli Protects the Mitochondrial Enzyme Rhodanese Against Heat Inactivation and Supports Folding at Elevated Temperatures. J.Biol.Chem. 267, 17631-17634.

Miller, D.M., Kurzban, G.P., Mendoza, J.A., Chirgwin, J.M., Hardies, S.C., and Horowitz, P.M. (1992) Recombinant Bovine Rhodanese: Purification and Comparison with Bovine Liver Rhodanese. Biochim.Biophys.Acta. 1121, 286-292.

Mendoza, J.A., Butler, M.C., and Horowitz, P.M. (1992) Characterization of a Stable, Reactivatable Complex Between Chaperonin 60 and Mitochondrial Rhodanese. J.Biol.Chem. 267, 24648-24654.

Mendoza, J.A., Lorimer, G.H., and Horowitz, P.M. (1991) Intermediates in the Chaperonin-Assisted Refolding of Rhodanese Are Trapped at Low Temperature and Show a Small Stoichiometry. J.Biol.Chem. 266, 16973-16976.

Mendoza, J.A., Rogers, E., Lorimer, G.H., and Horowitz, P.M. (1991) Unassisted Refolding of Urea Unfolded Rhodanese. J.Biol.Chem. 266, 13587-13591.

Mendoza, J.A., Rogers, E., Lorimer, G.H., and Horowitz, P.M. (1991) Chaperonins Facilitate the In Vitro Folding of Monomeric Mitochondrial Rhodanese. J.Biol.Chem. 266, 13044-13049.