期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2000
卷号：97
期号：16
页码：8926-8931
DOI：10.1073/pnas.150238697
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Homologous DNA recombination promotes genetic diversity and the maintenance of genome integrity, yet no enzymes with specificity for the Holliday junction (HJ)--a key DNA recombination intermediate--have been purified and characterized from metazoa or their viruses. Here we identify critical structural elements of RuvC, a bacterial HJ resolvase, in uncharacterized open reading frames from poxviruses and an iridovirus. The putative vaccinia virus resolvase was expressed as a recombinant protein, affinity purified, and shown to specifically bind and cleave a synthetic HJ to yield nicked duplex molecules. Mutation of either of two conserved acidic amino acids abrogated the catalytic activity of the A22R protein without affecting HJ binding. The presence of bacterial-type enzymes in metazoan viruses raises evolutionary questions.
