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

J. Biol. Chem., Vol. 279, Issue 13, 12067-12075, March 26, 2004

This Article Full Text Full Text (PDF) All Versions of this Article: 279/13/12067    most recent M313840200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map 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 Jones, C. E. Articles by Nossal, N. G. Search for Related Content PubMed PubMed Citation Articles by Jones, C. E. Articles by Nossal, N. G. Social Bookmarking                      What's this?

Bacteriophage T4 32 Protein Is Required for Helicase-dependent Leading Strand Synthesis When the Helicase Is Loaded by the T4 59 Helicase-loading Protein^*

Charles E. Jones, Timothy C. Mueser, and Nancy G. Nossal

From the Laboratory of Molecular and Cellular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0830 and the Department of Chemistry, University of Toledo, Toledo, Ohio 43606

In the bacteriophage T4 DNA replication system, T4 gene 59 protein binds preferentially to fork DNA and accelerates the loading of the T4 41 helicase. 59 protein also binds the T4 32 single-stranded DNA-binding protein that coats the lagging strand template. Here we explore the function of the strong affinity between the 32 and 59 proteins at the replication fork. We show that, in contrast to the 59 helicase loader, 32 protein does not bind forked DNA more tightly than linear DNA. 32 protein displays a strong binding polarity on fork DNA, binding with much higher affinity to the 5' single-stranded lagging strand template arm of a model fork, than to the 3' single-stranded leading strand arm. 59 protein promotes the binding of 32 protein on forks too short for cooperative binding by 32 protein. We show that 32 protein is required for helicase-dependent leading strand DNA synthesis when the helicase is loaded by 59 protein. However, 32 protein is not required for leading strand synthesis when helicase is loaded, less efficiently, without 59 protein. Leading strand synthesis by wild type T4 polymerase is strongly inhibited when 59 protein is present without 32 protein. Because 59 protein can load the helicase on forks without 32 protein, our results are best explained by a model in which 59 helicase loader at the fork prevents the coupling of the leading strand polymerase and the helicase, unless the position of 59 protein is shifted by its association with 32 protein.

Received for publication, December 18, 2003

^* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

To whom correspondence should be addressed: Laboratory of Molecular and Cellular Biology, Bldg. 8, Rm. 2A19, NIDDK, National Institutes of Health, Bethesda, MD 20892-0830. Tel.: 301-496-2724; Fax: 301-402-0240; E-mail: ngn{at}helix.nih.gov.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				E. Delagoutte, G. M. Goellner, J. Guo, G. Baldacci, and C. T. McMurray Single-stranded DNA-binding Protein in Vitro Eliminates the Orientation-dependent Impediment to Polymerase Passage on CAG/CTG Repeats J. Biol. Chem., May 9, 2008; 283(19): 13341 - 13356. [Abstract] [Full Text] [PDF]

				J. M. Devos, S. J. Tomanicek, C. E. Jones, N. G. Nossal, and T. C. Mueser Crystal Structure of Bacteriophage T4 5' Nuclease in Complex with a Branched DNA Reveals How Flap Endonuclease-1 Family Nucleases Bind Their Substrates J. Biol. Chem., October 26, 2007; 282(43): 31713 - 31724. [Abstract] [Full Text] [PDF]

				N. G. Nossal, A. M. Makhov, P. D. Chastain II, C. E. Jones, and J. D. Griffith Architecture of the Bacteriophage T4 Replication Complex Revealed with Nanoscale Biopointers J. Biol. Chem., January 12, 2007; 282(2): 1098 - 1108. [Abstract] [Full Text] [PDF]

				S. W. Nelson, J. Yang, and S. J. Benkovic Site-directed Mutations of T4 Helicase Loading Protein (gp59) Reveal Multiple Modes of DNA Polymerase Inhibition and the Mechanism of Unlocking by gp41 Helicase J. Biol. Chem., March 31, 2006; 281(13): 8697 - 8706. [Abstract] [Full Text] [PDF]

				O. Gangisetty, C. E. Jones, M. Bhagwat, and N. G. Nossal Maturation of Bacteriophage T4 Lagging Strand Fragments Depends on Interaction of T4 RNase H with T4 32 Protein Rather than the T4 Gene 45 Clamp J. Biol. Chem., April 1, 2005; 280(13): 12876 - 12887. [Abstract] [Full Text] [PDF]

				Z. Zhang, M. M. Spiering, M. A. Trakselis, F. T. Ishmael, J. Xi, S. J. Benkovic, and G. G. Hammes Assembly of the bacteriophage T4 primosome: Single-molecule and ensemble studies PNAS, March 1, 2005; 102(9): 3254 - 3259. [Abstract] [Full Text] [PDF]

				C. E. Jones, E. M. Green, J. A. Stephens, T. C. Mueser, and N. G. Nossal Mutations of Bacteriophage T4 59 Helicase Loader Defective in Binding Fork DNA and in Interactions with T4 32 Single-stranded DNA-binding Protein J. Biol. Chem., June 11, 2004; 279(24): 25721 - 25728. [Abstract] [Full Text] [PDF]