Linked Life Data

9265627

Source:http://linkedlifedata.com/resource/pubmed/id/9265627

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
34
pubmed:dateCreated
1997-9-25
pubmed:abstractText
Three T4 DNA polymerase accessory proteins (44P/62P and 45P) stimulate the polymerase (pol) activity and the 3'-5' exonuclease (exo) activity of T4 DNA polymerase (43P) on long, double-stranded DNA substrates. The 44P/62P "clamp loader" facilitates the binding of 45P, the "sliding clamp", to DNA that is primed for replication. Using a series of truncated 43P mutants, we identified a region at the extreme carboxy terminus of the DNA polymerase that is required for its interaction with accessory proteins. Truncation mutants of 43P lacking the carboxy-terminal 3, 6, or 11 residues retained full pol and exo activity on short synthetic primer-templates. However, the ability of the accessory proteins to enhance these activities on long double-stranded DNA templates was drastically reduced, and the extent of the reduction in activity was greater as more residues were deleted. One of the truncation mutants (N881), which had 17 residues removed from the carboxy terminus, showed reduced binding affinity and diminished pol activity but enhanced exo activity upon incubation with a small primer-template. The exo activity of the N881 mutant, on short, single-stranded DNA was unchanged, however, compared to the wild-type enzyme. These results are consistent with inferences drawn from the crystal structure of a DNA polymerase from a related T-even phage, RB69, where the carboxy-terminal 12 residues (equivalent to the 11 residues of 43P from phage T4) protrude from the thumb domain and are free to interact with complementary surfaces of the accessory proteins. The structural integrity of the thumb region in the N881 mutant is probably perturbed and could account for its reduced binding affinity and pol activity when incubated with short, double-stranded DNA substrates.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10474-81
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Residues at the carboxy terminus of T4 DNA polymerase are important determinants for interaction with the polymerase accessory proteins.
pubmed:affiliation
Protein Science Corporation, Meriden, Connecticut 06450, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.