HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Abbotts, J. Articles by Wilson, S. H. Search for Related Content PubMed PubMed Citation Articles by Abbotts, J. Articles by Wilson, S. H. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 263, Issue 29, 15094-15103, 10, 1988

Studies on the mechanism of Escherichia coli DNA polymerase I large fragment. Effect of template sequence and substrate variation on termination of synthesis

J Abbotts, DN SenGupta, G Zon and SH Wilson
Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892.

Termination of Escherichia coli DNA polymerase I large fragment after processive synthesis on natural and other well-defined template.primer systems has been examined. We found that after any given deoxynucleoside monophosphate incorporation termination occurs in a nonrandom manner with phi X174 DNA as template: Termination is much more likely at some nucleotide residues along the template than at others. Analysis of these stronger termination sites indicates that the template base:incoming nucleotide combination influences termination. Introduction of a double-stranded region along the phi X174 template induces termination, and reducing dNTP concentrations or substituting 2'-deoxynucleoside 5'-O-(1-thio)triphosphate substrates also increases termination. Observations with the phi X174 DNA template system were extended with a defined template containing 1 inosine residue in an otherwise d(T)n homopolymer. Termination at the I residue is modulated by dCTP and decreases as dCTP concentration increases. A similar relationship is seen with the dCTP (1-thio) derivative, but termination is higher at given concentrations of this derivative than with dCTP. Pyrophosphate decreases general processivity in this system, but does not counteract the effect of increasing dCTP. Hill plot analysis of the dCTP effect in the inosine-containing template system gave a linear plot with Hill coefficient of 0.34, suggesting that dCTP influences termination at several steps in the polymerase reaction scheme. Substituting a methylated template base for I also increased termination, producing very strong blocks to processive synthesis. The results are consistent with a model in which termination occurs with several enzyme forms that are in equilibrium in an ordered catalytic mechanism.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				M. Maitra, A. Gudzelak Jr., S.-X. Li, Y. Matsumoto, K. A. Eckert, J. Jager, and J. B. Sweasy Threonine 79 Is a Hinge Residue That Governs the Fidelity of DNA Polymerase beta by Helping to Position the DNA within the Active Site J. Biol. Chem., September 13, 2002; 277(38): 35550 - 35560. [Abstract] [Full Text] [PDF]

				S. G. Sarafianos, V. N. Pandey, N. Kaushik, and M. J. Modak Site-directed Mutagenesis of Arginine 72 of HIV-1 Reverse Transcriptase J. Biol. Chem., August 25, 1995; 270(34): 19729 - 19735. [Abstract] [Full Text] [PDF]

				G. J. Latham, E. Forgacs, W. A. Beard, R. Prasad, K. Bebenek, T. A. Kunkel, S. H. Wilson, and R. S. Lloyd Vertical-scanning Mutagenesis of a Critical Tryptophan in the "Minor Groove Binding Track" of HIV-1 Reverse Transcriptase. MAJOR GROOVE DNA ADDUCTS IDENTIFY SPECIFIC PROTEIN INTERACTIONS IN THE MINOR GROOVE J. Biol. Chem., May 12, 2000; 275(20): 15025 - 15033. [Abstract] [Full Text] [PDF]