1tva
From Proteopedia
HUMAN DNA POLYMERASE BETA COMPLEXED WITH NICKED DNA CONTAINING A MISMATCHED TEMPLATE THYMIDINE AND INCOMING CYTIDINE
Overview
DNA polymerases generally select the correct nucleotide from a pool of structurally similar molecules to preserve Watson-Crick base-pairing rules. We report the structure of DNA polymerase beta with DNA mismatches situated in the polymerase active site. This was achieved by using nicked product DNA that traps the mispair (template-primer, A-C or T-C) in the nascent base pair binding pocket. The structure of each mispair complex indicates that the bases do not form hydrogen bonds with one another, but form a staggered arrangement where the bases of the mispair partially overlap. This prevents closure/opening of the N subdomain that is believed to be required for catalytic cycling. The partially open conformation of the N subdomain results in distinct hydrogen bonding networks that are unique for each mispair. These structures define diverse molecular aspects of misinsertion that are consistent with the induced-fit model for substrate specificity.
About this Structure
1TVA is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structural insights into DNA polymerase beta deterrents for misincorporation support an induced-fit mechanism for fidelity., Krahn JM, Beard WA, Wilson SH, Structure. 2004 Oct;12(10):1823-32. PMID:15458631 Page seeded by OCA on Sat May 3 10:24:40 2008
