An archaeal Holliday junction resolving enzyme from Sulfolobus solfataricus exhibits unique properties

被引:48
作者
Kvaratskhelia, M [1 ]
White, MF [1 ]
机构
[1] Univ Dundee, MSI WTB Complex, Dept Biochem, Dundee DD1 5EH, Scotland
基金
英国生物技术与生命科学研究理事会;
关键词
Holliday junction; archaea; endonuclease; resolving enzyme; homologous recombination;
D O I
10.1006/jmbi.1999.3363
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The rearrangement and repair of DNA by homologous recombination often involves the creation of Holliday junctions, which must be cleaved by junction-specific endonucleases to yield recombinant duplex DNA products. Holliday junction resolving enzymes are a ubiquitous class of proteins with diverse structural and mechanistic characteristics. We have characterised an endonuclease (Hje) from the thermophilic crenarchaeote Sulfolobus solfataricus that exhibits a high degree of specificity for Holliday junctions via an apparently novel mechanism. Hje resolves four-way DNA junctions by the introduction of paired nicks in a reaction that is independent of the local nucleotide sequence, but is restricted solely to strands that are continuous in the stacked-X form of the junction. Three-way DNA junctions are cleaved only when the presence of a bulge in one strand allows the junction to stack in an analogous manner to four-way junctions. These properties differentiate Hje from all other known junction resolving enzymes. (C) 2000 Academic Press.
引用
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页码:193 / 202
页数:10
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