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1nk4
From Proteopedia
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GUANINE-GUANINE MISMATCH AT THE POLYMERASE ACTIVE SITE
Overview
Accurate DNA replication is essential for genomic stability. One mechanism, by which high-fidelity DNA polymerases maintain replication accuracy, involves stalling of the polymerase in response to covalent incorporation, of mismatched base pairs, thereby favoring subsequent mismatch excision., Some polymerases retain a "short-term memory" of replication errors, responding to mismatches up to four base pairs in from the primer, terminus. Here we a present a structural characterization of all 12, possible mismatches captured at the growing primer terminus in the active, site of a polymerase. Our observations suggest four mechanisms that lead, to mismatch-induced stalling of the polymerase. Furthermore, we have, observed the effects of extending a mismatch up to six base pairs from the, primer terminus and find that long-range distortions in the DNA transmit, the presence of the mismatch back to the enzyme active site, suggesting, the structural basis for the short-term memory of replication errors.
About this Structure
1NK4 is a Protein complex structure of sequences from Geobacillus stearothermophilus with SUC, SO4 and MG as ligands. Active as DNA-directed DNA polymerase, with EC number 2.7.7.7 Full crystallographic information is available from OCA.
Reference
Structures of mismatch replication errors observed in a DNA polymerase., Johnson SJ, Beese LS, Cell. 2004 Mar 19;116(6):803-16. PMID:15035983
Page seeded by OCA on Sat Nov 24 23:16:49 2007
