3bep
From Proteopedia
Structure of a sliding clamp on DNA
Overview
The structure of the E. coli beta clamp polymerase processivity factor has been solved in complex with primed DNA. Interestingly, the clamp directly binds the DNA duplex and also forms a crystal contact with the ssDNA template strand, which binds into the protein-binding pocket of the clamp. We demonstrate that these clamp-DNA interactions function in clamp loading, perhaps by inducing the ring to close around DNA. Clamp binding to template ssDNA may also serve to hold the clamp at a primed site after loading or during switching of multiple factors on the clamp. Remarkably, the DNA is highly tilted as it passes through the beta ring. The pronounced 22 degrees angle of DNA through beta may enable DNA to switch between multiple factors bound to a single clamp simply by alternating from one protomer of the ring to the other.
About this Structure
3BEP is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structure of a sliding clamp on DNA., Georgescu RE, Kim SS, Yurieva O, Kuriyan J, Kong XP, O'Donnell M, Cell. 2008 Jan 11;132(1):43-54. PMID:18191219 Page seeded by OCA on Sun May 4 20:41:33 2008
