Structure of Hjc, a Holliday junction resolvase, from Sulfolobus solfataricus

被引:73
作者
Bond, CS [1 ]
Kvaratskhelia, M
Richard, D
White, MF
Hunter, WN
机构
[1] Univ Dundee, Wellcome Trust Bioctr, Dundee DD1 5EH, Tayside, Scotland
[2] Univ St Andrews, Ctr Biomol Sci, St Andrews KY16 9ST, Fife, Scotland
基金
英国惠康基金;
关键词
D O I
10.1073/pnas.091613398
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
The 2.15-Angstrom structure of Hjc, a Holliday junction-resolving enzyme from the archaeon Sulfolobus solfataricus, reveals extensive structural homology with a superfamily of nucleases that includes type II restriction enzymes. Hjc is a dimer with a large DNA-binding surface consisting of numerous basic residues surrounding the metal-binding residues of the active sites. Residues critical for catalysis, identified on the basis of sequence comparisons and site-directed mutagenesis studies, are clustered to produce two active sites in the dimer, about 29 Angstrom apart, consistent with the requirement for the introduction of paired nicks in opposing strands of the four-way DNA junction substrate. Hjc displays similarity to the restriction endonucleases in the way its specific DNA-cutting pattern is determined but uses a different arrangement of nuclease subunits. Further structural similarity to a broad group of metal/phosphate-binding proteins, including conservation of active-site location, is observed. A high degree of conservation of surface electrostatic character is observed between Hjc and T4-phage endonuclease VII despite a complete lack of structural homology. A model of the Hjc-Holliday junction complex is proposed, based on the available functional and structural data.
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页码:5509 / 5514
页数:6
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