The roles of the residues on the channel β-hairpin and loop structures of simian virus 40 hexameric helicase

被引:49
作者
Shen, JP
Gai, DH
Patrick, A
Greenleaf, WB
Chen, XJS [1 ]
机构
[1] Univ So Calif, Dept Mol & Computat Biol, Los Angeles, CA 90089 USA
[2] Univ Colorado, Hlth Sci Ctr, Dept Biochem & Mol Genet, Aurora, CO 80045 USA
关键词
AAA(+); molecular machine; replication; large T antigen;
D O I
10.1073/pnas.0409646102
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Simian virus 40 large tumor antigen is required for DNA unwinding during viral replication. The helicase-active form of large tumor antigen is a ring-shaped hexamer/clouble hexamer, which has a positively charged hexameric channel for interacting with DNA. On the hexameric channel surface are six beta-hairpin structures and loops, emanating from each of the six subunits. At the tips of the P-hairpin and the loop structures are two ring-shaped residues, H513 and F459, respectively. Additionally, two positively charged residues, K512 and K516, are near the tip of the beta-hairpin. The positions of these ring-shaped and positively charged residues suggest that they may play a role in binding DNA for helicase function. To understand the roles of these residues in helicase function, we obtained a set of mutants and examined various activities, including oligomerization, ATPase, DNA binding, and helicase activities. We found that substitution of these residues by Ala abolished helicase activity. Extensive mutagenesis showed that substitutions by ring-shaped residues (W and Y) at position F459 and by residues with hydrophobic or long aliphatic side chains (W, Y, F, L, M, and R) at position H513 supported helicase activity. Our study demonstrated that the four residues (F459, H513, K512, and K516) play a critical role in interacting with DNA for helicase function. The results suggest a possible mechanism to explain how these residues, as well as the beta-hairpin and the loop structures on which the residues reside, participate in binding and translocating DNA for origin melting and unwinding.
引用
收藏
页码:11248 / 11253
页数:6
相关论文
共 26 条
[1]   The X-ray structure of the papillomavirus helicase in complex with its molecular matchmaker E2 [J].
Abbate, EA ;
Berger, JM ;
Botchan, MR .
GENES & DEVELOPMENT, 2004, 18 (16) :1981-1996
[2]   Structure of a repair enzyme interrogating undamaged DNA elucidates recognition of damaged DNA [J].
Banerjee, A ;
Yang, W ;
Karplus, M ;
Verdine, GL .
NATURE, 2005, 434 (7033) :612-618
[3]   The structures of HsIU and ATP-dependent protease HsIU-HsIV [J].
Bochtler, M ;
Hartmann, C ;
Song, HK ;
Bourenkov, GP ;
Bartunik, HD ;
Huber, R .
NATURE, 2000, 403 (6771) :800-805
[4]   BINDING AND UNWINDING - HOW T-ANTIGEN ENGAGES THE SV40 ORIGIN OF DNA-REPLICATION [J].
BOROWIEC, JA ;
DEAN, FB ;
BULLOCK, PA ;
HURWITZ, J .
CELL, 1990, 60 (02) :181-184
[5]   DIFFERENTIAL INDUCTION OF STRUCTURAL-CHANGES IN THE SIMIAN VIRUS-40 ORIGIN OF REPLICATION BY T-ANTIGEN [J].
BOROWIEC, JA ;
DEAN, FB ;
HURWITZ, J .
JOURNAL OF VIROLOGY, 1991, 65 (03) :1228-1235
[6]   The initiation of Simian Virus 40 DNA replication in vitro [J].
Bullock, PA .
CRITICAL REVIEWS IN BIOCHEMISTRY AND MOLECULAR BIOLOGY, 1997, 32 (06) :503-568
[7]  
DEAN FB, 1991, J BIOL CHEM, V266, P5062
[8]   SIMIAN VIRUS-40 LARGE T-ANTIGEN - THE PUZZLE, THE PIECES, AND THE EMERGING PICTURE [J].
FANNING, E .
JOURNAL OF VIROLOGY, 1992, 66 (03) :1289-1293
[9]   The structure and function of MCM from archaeal M-thermoautotrophicum [J].
Fletcher, RJ ;
Bishop, BE ;
Leon, RP ;
Sclafani, RA ;
Ogata, CM ;
Chen, XJS .
NATURE STRUCTURAL BIOLOGY, 2003, 10 (03) :160-167
[10]   Structural basis for removal of adenine mispaired with 8-oxoguanine by MutY adenine DNA glycosylase [J].
Fromme, JC ;
Banerjee, A ;
Huang, SJ ;
Verdine, GL .
NATURE, 2004, 427 (6975) :652-656