title: Vaccinia virus DNA topoisomerase I preferentially removes positive supercoils from DNA.
abstract: Type I DNA topoisomerases homologous to Escherichia coli topoisomerase I normally only remove negative supercoils from DNA. Topoisomerases I from various eukaryotes share sequence homology and remove both positive and negative supercoils from DNA. Here we report that vaccinia virus topoisomerase I has significant difference in substrate preference from the other homologous type I topoisomerases. Vaccinia virus topoisomerase I shows a definite preference for removal of positive supercoils. In contrast, topoisomerase I from human, wheat germ and Saccharomyces cerevisiae has little preference between positive and negative supercoils. The vaccinia enzyme may have evolved for functions required for optimal viral growth. topoisomerases.
authors.affiliation: Department of Biochemistry and Molecular Biology, New York Medical College, Vallhalla, 10595, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Fernandez-Beros
authors.forename: Y C
authors.initials: YC
authors.lastname: Tse-Dinh
mesh_terms: D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D008954:Models, Biological; D009675:Novobiocin / Q000494:pharmacology; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013379:Substrate Specificity; D014158:Transcription, Genetic; D014908:Triticum / Q000201:enzymology; D014616:Vaccinia virus / Q000201:enzymology* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical; D009675:Novobiocin; D004264:DNA Topoisomerases, Type I