1hpm
From Proteopedia
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HOW POTASSIUM AFFECTS THE ACTIVITY OF THE MOLECULAR CHAPERONE HSC70. II. POTASSIUM BINDS SPECIFICALLY IN THE ATPASE ACTIVE SITE
Overview
Crystallographic anomalous scattering from potassium at 1.7 A resolution, reveals two monovalent ions that interact with MgADP and P(i) in the, nucleotide binding cleft of wild-type recombinant bovine Hsc70 ATPase, fragment. K+ at site 1 interacts with oxygens of the beta-phosphate of, ADP, whereas K+ at site 2 interacts with an oxygen of P(i). Both K+ ions, also interact with specific H2O molecules in the first hydration shell of, the octahedrally coordinated Mg2+ ion and with specific protein ligands., In crystals that have Na+ present, K+ is replaced by a Na+ ion at site 1, and by a Na(+)-H2O pair at site 2. The K+ ions are positioned where they, could stabilize binding of a beta,gamma-bidentate MgATP complex with, Hsc70, as well as a transition state during ATP hydrolysis, suggesting, that monovalent ions act as specific metal cofactors in the ATPase, reaction of Hsc70.
About this Structure
1HPM is a Single protein structure of sequence from Bos taurus with MG, PO4, K, CL and ADP as ligands. Active as Adenosinetriphosphatase, with EC number 3.6.1.3 Full crystallographic information is available from OCA.
Reference
How potassium affects the activity of the molecular chaperone Hsc70. II. Potassium binds specifically in the ATPase active site., Wilbanks SM, McKay DB, J Biol Chem. 1995 Feb 3;270(5):2251-7. PMID:7836458
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