title: Structural and functional studies of the Leishmania braziliensis mitochondrial Hsp70: Similarities and dissimilarities to human orthologues.
abstract: Heat shock protein 70 kDa (Hsp70) is a conserved molecular chaperone family involved in several functions related to protein homeostasis. In eukaryotes, Hsp70 homologues are found in all cell compartments. The mitochondrial Hsp70 isoform (mtHsp70) is involved in import of mitochondrial matrix proteins as well as their folding and maturation. Moreover, mtHsp70 has the propensity to self-aggregate, and it depends on the action of the co-chaperone Hsp70-escort protein 1 (Hep1) to be produced functional. Here, we analyze the solution structure and function of mtHsp70 of Leishmania braziliensis (LbmtHsp70). This recombinant protein was obtained folded, in the monomeric state and it has an elongated shape. We observed that LbmtHsp70 suffers thermal aggregation that depends on the protein concentration and is composed of domains with different thermal stabilities. LbmtHsp70 interacted with adenosine nucleotides with a thermodynamic signature different from those reported for human orthologues and interacted, driven by both enthalpy and entropy, with L. braziliensis Hep1 (LbHep1) with a nanomolar dissociation constant. Moreover, LbHep1 stimulated the LbmtHsp70 ATPase activity. Since little is known about mitochondrial Hsp70, particularly in protozoa, we believe that our data are of interest for understanding protozoan Hsp70 machinery.
authors.affiliation: Institute of Chemistry of Sao Carlos, University of Sao Paulo, Sao Carlos, SP, P.O. Box 780, 13560-970, Brazil.
authors.forename: Paulo R
authors.initials: PR
authors.lastname: Dores-Silva
authors.affiliation: Institute of Chemistry of Sao Carlos, University of Sao Paulo, Sao Carlos, SP, P.O. Box 780, 13560-970, Brazil.
authors.forename: Letícia S
authors.initials: LS
authors.lastname: Nishimura
authors.affiliation: Institute of Chemistry of Sao Carlos, University of Sao Paulo, Sao Carlos, SP, P.O. Box 780, 13560-970, Brazil.
authors.forename: Vanessa T R
authors.initials: VT
authors.lastname: Kiraly
authors.affiliation: Institute of Chemistry of Sao Carlos, University of Sao Paulo, Sao Carlos, SP, P.O. Box 780, 13560-970, Brazil. Electronic address: borgesjc@iqsc.usp.br.
authors.forename: Júlio C
authors.initials: JC
authors.lastname: Borges
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D000255:Adenosine Triphosphate / Q000737:chemistry; D003593:Cytoplasm / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D057446:Hydrodynamics; D006868:Hydrolysis; D007892:Leishmania braziliensis / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D017510:Protein Folding; D020033:Protein Isoforms / Q000378:metabolism; D015800:Protozoan Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; C492001:HSPA9 protein, human; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; D020033:Protein Isoforms; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; C063842:dnaK protein, E coli
keywords: Leishmania braziliensis; Mitochondria; Molecular chaperones; mtHsp70