Linked Life Data

9642062

Source:http://linkedlifedata.com/resource/pubmed/id/9642062

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1998-7-21
pubmed:abstractText
Here, three highly conserved amino acid residues have been characterized to function as ssDNA binding ligands at the 3'-5' exonuclease active site of phi29 DNA polymerase. One of these residues, Phe65, belongs to motif Exo II, previously described to contain an invariant aspartate and an invariant asparagine involved in catalysis and ssDNA binding, respectively. The other two residues, Ser122 and Leu123, form a newly identified motif "(S/T)Lx2h", and are the homologous counterparts of Pol I residues Asp457 and Met458, and of T4 DNA polymerase residues Ser286 and Leu287, the latter three residues shown to contact ssDNA at their corresponding cocrystal 3D structures. Site-directed mutagenesis and biochemical analysis of eight phi29 DNA polymerase mutant proteins at residues Phe65, Ser122 and Leu123 indicated their functional importance for: (1) a stable interaction with ssDNA; (2) 3'-5' exonucleolysis of ssDNA substrates; (3) proofreading of DNA polymerization errors. Extrapolation to the crystal structures of Klenow and T4 DNA polymerases indicates that the invariant aromatic ring contiguous to the catalytic aspartate of the Exo II motif, corresponding to Tyr423 in Klenow, Phe218 in T4, and Phe65 in phi29 DNA polymerase, appears to be critical to orient the ssDNA substrate in a stable conformation to allow 3'-5' exonucleolytic catalysis. This is the first time that the functional importance of this invariant residue, belonging to the Exo II motif, has been demonstrated.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-2836
pubmed:author
pubmed:copyrightInfo
Copyright 1998 Academic Press Limited.
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
807-22
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Mutational analysis of phi29 DNA polymerase residues acting as ssDNA ligands for 3'-5' exonucleolysis.
pubmed:affiliation
Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma, Canto Blanco, Madrid, 28049, Spain.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't