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|2fll, resolution 2.60Å ()|
|Gene:||POLI, RAD30B (Homo sapiens)|
|Related:||1t3n, 2azl, 2fln, 2flp|
Ternary complex of human DNA polymerase iota with DNA and dTTP
Substrate-induced conformational change of the protein is the linchpin of enzymatic reactions. Replicative DNA polymerases, for example, convert from an open to a closed conformation in response to dNTP binding. Human DNA polymerase-iota (hPoliota), a member of the Y family of DNA polymerases, differs strikingly from other polymerases in its much higher proficiency and fidelity for nucleotide incorporation opposite template purines than opposite template pyrimidines. We present here a crystallographic analysis of hPoliota binary complexes, which together with the ternary complexes show that, contrary to replicative DNA polymerases, the DNA, and not the polymerase, undergoes the primary substrate-induced conformational change. The incoming dNTP "pushes" templates A and G from the anti to the syn conformation dictated by a rigid hPoliota active site. Together, the structures posit a mechanism for template selection wherein dNTP binding induces a conformational switch in template purines for productive Hoogsteen base pairing.
An incoming nucleotide imposes an anti to syn conformational change on the templating purine in the human DNA polymerase-iota active site., Nair DT, Johnson RE, Prakash L, Prakash S, Aggarwal AK, Structure. 2006 Apr;14(4):749-55. PMID:16615915
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.