Linked Life Data

21454515

Source:http://linkedlifedata.com/resource/pubmed/id/21454515

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2011-5-30
pubmed:databankReference
pubmed:abstractText
To achieve accurate DNA synthesis, DNA polymerases must rapidly sample and discriminate against incorrect nucleotides. Here we report the crystal structure of a high fidelity DNA polymerase I bound to DNA primer-template caught in the act of binding a mismatched (dG:dTTP) nucleoside triphosphate. The polymerase adopts a conformation in between the previously established "open" and "closed" states. In this "ajar" conformation, the template base has moved into the insertion site but misaligns an incorrect nucleotide relative to the primer terminus. The displacement of a conserved active site tyrosine in the insertion site by the template base is accommodated by a distinctive kink in the polymerase O helix, resulting in a partially open ternary complex. We suggest that the ajar conformation allows the template to probe incoming nucleotides for complementarity before closure of the enzyme around the substrate. Based on solution fluorescence, kinetics, and crystallographic analyses of wild-type and mutant polymerases reported here, we present a three-state reaction pathway in which nucleotides either pass through this intermediate conformation to the closed conformation and catalysis or are misaligned within the intermediate, leading to destabilization of the closed conformation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
3
pubmed:volume
286
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
19758-67
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
The structure of a high fidelity DNA polymerase bound to a mismatched nucleotide reveals an "ajar" intermediate conformation in the nucleotide selection mechanism.
pubmed:affiliation
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural