Structural and functional studies of Hsp70-escort protein-Hep1-of Leishmania braziliensis

Author(s)

Dores-Silva, P. R. ^[1] ; Beloti, L. L. ^[1] ; Minari, K. ^{[1, 2]} ; Silva, S. M. O. ^[1] ; Barbosa, L. R. S. ^[3] ; Borges, J. C. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Chem Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Fed Univ Sao Carlos UFSCar, Postgrad Program Evolutionary Genet & Mol Biol, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Sao Paulo, Inst Phys, BR-05508090 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: International Journal of Biological Macromolecules; v. 79, p. 903-912, AUG 2015.
• Web of Science Citations: 4

Abstract

Hep1 is a mitochondrial Hsp70 (mtHsp70) co-chaperone that presents a zinc finger domain essential for its function. This co-chaperone acts to maintain mtHsp70 in its soluble and functional state. In this work, we have demonstrated that Leishmania braziliensis mtHsp70 (LbmtHsp70) is also dependent on the assistance of Hep1. To understand the L. braziliensis Hep1 (LbHep1) structure function relationship, we produced LbHep1 and two truncated mutants corresponding to the C-terminal zinc finger domain and the N-terminal region. We observed that LbHep1 is composed of an unfolded N-terminal region and a beta-sheet-folded C-terminal domain, which holds the zinc-binding motif. Both LbHep1 and the zinc finger domain construction maintained LbmtHsp70 solubility in co-expression systems after cell lysis. In solution, LbHep1 behaved as a highly elongated monomer, probably due to the unfolded N-terminal region. Furthermore, we also observed that the zinc ion interacted with LbHep1 with high affinity and was critical for LbHep1 structure and stability because its removal from LbHep1 solutions altered the protein structure and stability. In vitro, LbHep1 protected, in sub-stoichiometric fashion, LbmtHsp70 from thermally induced aggregation but did not present intrinsic chaperone activity on model client proteins. Therefore, LbHep1 is a specific chaperone for LbmtHsp70. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 11/23110-0 - Using isothermal titration calorimetry for the determination of thermodynamic properties of protein-ligand and protein-protein interactions
• Grantee: Julio Cesar Borges
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/16646-0 - Human mortalin: interaction with co-chaperones, p53 and mutants, aggregation kinectics, regulation/modulation and vesicle secretion
• Grantee: Paulo Roberto das Dores da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/07206-6 - Studies of the mitochondrial HSP70 of human and protozoa: structural and functional approaches
• Grantee: Julio Cesar Borges
• Support Opportunities: Regular Research Grants