Molecular chaperones of the Heat Shock Protein 70(Hsp7O) family bind unfolded polypeptide substrates to stabilize or alter their conformation and hydrolyze ATP to facilitate polypeptide release. The ATP hydrolysis of Hsp70 is regulated by another protein chaperon family Heat Shock Protein 40(Hsp4O)(1). It has been reported that Hsp4O may bind polypeptides with secondary structure, interact directly with Hsp70 and stimulate the ATP hydrolysis of Hsp70. Hsp4O itself can also bind denatured polypeptides and refold them as an independent protein chaperone(2). Sis I is a member of Hsp4O protein family in yeast Saccharomyces cerevisiae and it is essential for cell viability(3). We have crystallized the protein Sis I recently, the crystals diffract to 2.7A at SSRL station 7- 1. We propose to solve the crystal structure of Sis I by MAD method on BioCARS Station 14 BM-D.

Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Durbin, S M; Clevenger, T; Graber, T et al. (2012) X-ray pump optical probe cross-correlation study of GaAs. Nat Photonics 6:111-114
Neutze, Richard; Moffat, Keith (2012) Time-resolved structural studies at synchrotrons and X-ray free electron lasers: opportunities and challenges. Curr Opin Struct Biol 22:651-9
Horsman, Geoff P; Ke, Jiyuan; Dai, Shaodong et al. (2006) Kinetic and structural insight into the mechanism of BphD, a C-C bond hydrolase from the biphenyl degradation pathway. Biochemistry 45:11071-86