This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1nk8
From Proteopedia
|
A BACILLUS DNA POLYMERASE I PRODUCT COMPLEX BOUND TO A GUANINE-THYMINE MISMATCH AFTER A SINGLE ROUND OF PRIMER EXTENSION, FOLLOWING INCORPORATION OF DCTP.
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
1NK8 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 23:18:05 2007
