title: Structure of the N-terminal fragment of topoisomerase V reveals a new family of topoisomerases.
abstract: Topoisomerases are involved in controlling and maintaining the topology of DNA and are present in all kingdoms of life. Unlike all other types of topoisomerases, similar type IB enzymes have only been identified in bacteria and eukarya. The only putative type IB topoisomerase in archaea is represented by Methanopyrus kandleri topoisomerase V. Despite several common functional characteristics, topoisomerase V shows no sequence similarity to other members of the same type. The structure of the 61 kDa N-terminal fragment of topoisomerase V reveals no structural similarity to other topoisomerases. Furthermore, the structure of the active site region is different, suggesting no conservation in the cleavage and religation mechanism. Additionally, the active site is buried, indicating the need of a conformational change for activity. The presence of a topoisomerase in archaea with a unique structure suggests the evolution of a separate mechanism to alter DNA.
authors.affiliation: Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208-3500, USA.
authors.forename: Bhupesh
authors.initials: B
authors.lastname: Taneja
authors.forename: Asmita
authors.initials: A
authors.lastname: Patel
authors.forename: Alexei
authors.initials: A
authors.lastname: Slesarev
authors.forename: Alfonso
authors.initials: A
authors.lastname: Mondragón
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D003461:Crystallography; D004264:DNA Topoisomerases, Type I / Q000737:chemistry* / Q000235:genetics; D019605:Euryarchaeota / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011487:Protein Conformation; D017422:Sequence Analysis, DNA; D013050:Spectrometry, Fluorescence
chemical_list: C082698:DNA topoisomerase V; D004264:DNA Topoisomerases, Type I