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

J. Biol. Chem., Vol. 279, Issue 1, 127-132, January 2, 2004

This Article Full Text Full Text (PDF) All Versions of this Article: 279/1/127    most recent M309860200v1 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 Google Scholar Google Scholar Articles by Lou, H. Articles by Huang, L. Search for Related Content PubMed PubMed Citation Articles by Lou, H. Articles by Huang, L.

Modulation of Hyperthermophilic DNA Polymerase Activity by Archaeal Chromatin Proteins^*

Huiqiang Lou, Zhenhong Duan, Xiaofeng Huo, and Li Huang

From the State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China

Sulfolobus synthesizes a large quantity of highly conserved 7-kDa DNA-binding proteins suspected to be involved in chromosomal organization. The effect of the 7-kDa proteins on the polymerization and 3'-5' exonuclease activities of a family B DNA polymerase (polB1) from the hyperthermophilic archaeon Sulfolobus solfataricus was investigated. polB1 degraded both single-stranded DNA and double-stranded DNA at similar rates in vitro at temperatures of physiological relevance. The 7-kDa proteins were capable of significantly inhibiting the excision and enhancing the extension of matched template primers by the polymerase. However, the proteins did not protect single-stranded DNA from cleavage by polB1. In addition, the 7-kDa proteins did not affect the proofreading ability of polB1 and were not inhibitory to the excision of mismatched primers by the polymerase. The dNTP concentrations required for the effective inhibition of the 3'-5' exonuclease activity of polB1 were lowered from 1 mM in the absence of the 7-kDa proteins to 50 µM in the presence of the proteins at 65 °C. Our data suggest that the 7-kDa chromatin proteins serve to modulate the extension and excision activities of the hyperthermophilic DNA polymerase, reducing the cost of proofreading by the enzyme at high temperature.

Received for publication, September 5, 2003 , and in revised form, October 15, 2003.

^* This work was supported in part by Grants 39925001 and 30030010 from the National Science Foundation of China and Grant KSCX2-SW-112 from the Chinese Academy of Sciences (to L. H.). 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.

Contributed equally to this work.

To whom correspondence should be addressed. Tel.: 86-10-62624971; Fax: 86-10-62653468; E-mail: huangl{at}sun.im.ac.cn.