2B26

The crystal structure of the protein complex of yeast Hsp40 Sis1 and Hsp70 Ssa1

Summary for 2B26

• Entry DOI: 10.2210/pdb2b26/pdb
• Descriptor: SIS1 protein, Heat shock 70 kDa protein cognate 2 (2 entities in total)
• Functional Keywords: hsp40 sis1 hsp70 ssa1, chaperone-protein transport complex, chaperone/protein transport
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Total number of polymer chains: 4
• Total formula weight: 59252.38

Authors

Li, J.,Wu, Y.,Qian, X.,Sha, B. (deposition date: 2005-09-16, release date: 2006-09-19, Last modification date: 2024-02-14)

Primary citation

Li, J.,Wu, Y.,Qian, X.,Sha, B.
Crystal structure of yeast Sis1 peptide-binding fragment and Hsp70 Ssa1 C-terminal complex.
Biochem.J., 398:353-360, 2006

PubMed Abstract: Heat shock protein (Hsp) 40 facilitates the critical role of Hsp70 in a number of cellular processes such as protein folding, assembly, degradation and translocation in vivo. Hsp40 and Hsp70 stay in close contact to achieve these diverse functions. The conserved C-terminal EEVD motif in Hsp70 has been shown to regulate Hsp40-Hsp70 interaction by an unknown mechanism. Here, we provide a structural basis for this regulation by determining the crystal structure of yeast Hsp40 Sis1 peptide-binding fragment complexed with the Hsp70 Ssa1 C-terminal. The Ssa1 extreme C-terminal eight residues, G634PTVEEVD641, form a beta-strand with the domain I of Sis1 peptide-binding fragment. Surprisingly, the Ssa1 C-terminal binds Sis1 at the site where Sis1 interacts with the non-native polypeptides. The negatively charged residues within the EEVD motif in Ssa1 C-terminal form extensive charge-charge interactions with the positively charged residues in Sis1. The structure-based mutagenesis data support the structural observations.

PubMed: 16737444
DOI: 10.1042/BJ20060618

Experimental method

X-RAY DIFFRACTION (3.2 Å)