Protein folding in the cell is usually aided by molecular chaperones, which the Hsp70 family (Hsp = heat shock protein) plays important roles, aiding in the folding of newly synthesized proteins, in the translocation, and others. Co-chaperones J-domain proteins (JDP) cooperate with Hsp70, binding to partially folded proteins (client) and delivering them to Hsp70. Although the functions of these proteins are determined, their three-dimensional structures and the interaction mechanism of JDP with the client and with Hsp70, for being transient, are not well established. Besides that, the absence of data is because the structural characterization of these proteins is hampered by the high molecular mass of these macromolecules, the presence of a large flexible region in the JDP and also because this interaction is transient. However, our research group has made important contributions about the structure and function of some JDP, characterizing the quaternary structure by low-angle scattering - SAXS (Ramos et al., 2008), and solving the three-dimensional NMR structure of the functional domain of JDP, which interacts with Hsp70 (Pinheiro et al., 2018). Also performed dynamics experiments, to understand the relationship between the domains, and which residues are involved in the interaction with the Hsp70 (manuscript in preparation). Since then we have been planning and executing experiments to solve the structure and dynamics of this co-chaperone in high resolution. The initial data obtained are very promising and suggest that we are close to accomplishing a feat in Brazil, determining the high resolution NMR structure of a dimeric protein, where each monomer has about 40 kDa and the understanding the interaction mechanism between this protein and the Hsp70 by cryo-electron microscopy. To reach this challenge, the collaboration between research groups at UNICAMP, UFRJ and IBS (Grenoble - France) is fundamental and such collaboration will be possible only through the candidate for the fellowships.
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