Publication Date:
1992-06-19
Description:
The mechanism by which DNA helicases unwind DNA was tested; an "unwinding complex" between the SV40 large tumor antigen (T antigen) and a DNA molecule designed to resemble a replication fork was probed. In an adenosine triphosphate (ATP)-dependent reaction, T antigen quantitatively recognized this synthetic replication fork and bound the DNA primarily as a hexamer. The T antigen bound only one of the two strands at the fork, an asymmetric interaction consistent with the 3'----5' directionality of the DNA helicase activity of T antigen. Binding to chemically modified DNA substrates indicated that the DNA helicase recognized the DNA primarily through the sugar-phosphate backbone. Ethylation of six top strand phosphates at the junction of single-stranded and double-stranded DNA inhibited the DNA helicase activity of T antigen. Neither a 3' single-stranded end on the DNA substrate nor ATP hydrolysis was required for T antigen to bind the replication fork. These data suggest that T antigen can directly bind the replication fork through recognition of a fork-specific structure.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉SenGupta, D J -- Borowiec, J A -- AI29963/AI/NIAID NIH HHS/ -- P30CA 16087/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 1992 Jun 19;256(5064):1656-61.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, New York University Medical Center, NY 10016.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1319087" target="_blank"〉PubMed〈/a〉
Keywords:
Adenosine Triphosphate/pharmacology
;
Antigens, Polyomavirus Transforming/*physiology
;
DNA Helicases/physiology
;
DNA Replication/*immunology
;
DNA, Single-Stranded/metabolism
;
Diethyl Pyrocarbonate/pharmacology
;
Dose-Response Relationship, Drug
;
Electrophoresis, Polyacrylamide Gel
;
Ethylnitrosourea/pharmacology
;
Formates/pharmacology
;
Potassium Permanganate/pharmacology
;
Sulfuric Acid Esters/pharmacology
;
Time Factors
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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