Ligand-induced Conformational Shift in the N-terminal Domain of GRP94, an Hsp90 Chaperone.
Immormino, R.M., Dollins, D.E., Shaffer, P.L., Soldano, K.L., Walker, M.A., Gewirth, D.T.(2004) J Biol Chem 279: 46162-46171
- PubMed: 15292259 
- DOI: https://doi.org/10.1074/jbc.M405253200
- Primary Citation of Related Structures:  
1TBW, 1TC0, 1TC6 - PubMed Abstract: 
GRP94 is the endoplasmic reticulum paralog of cytoplasmic Hsp90. Models of Hsp90 action posit an ATP-dependent conformational switch in the N-terminal ligand regulatory domain of the chaperone. However, crystal structures of the isolated N-domain of Hsp90 in complex with a variety of ligands have yet to demonstrate such a conformational change. We have determined the structure of the N-domain of GRP94 in complex with ATP, ADP, and AMP. Compared with the N-ethylcarboxamidoadenosine and radicicol-bound forms, these structures reveal a large conformational rearrangement in the protein. The nucleotide-bound form exposes new surfaces that interact to form a biochemically plausible dimer that is reminiscent of those seen in structures of MutL and DNA gyrase. Weak ATP binding and a conformational change in response to ligand identity are distinctive mechanistic features of GRP94 and suggest a model for how GRP94 functions in the absence of co-chaperones and ATP hydrolysis.
Organizational Affiliation: 
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.