1vcc

AMINO TERMINAL 9KDA DOMAIN OF VACCINIA VIRUS DNA TOPOISOMERASE I RESIDUES 1-77, EXPERIMENTAL ELECTRON DENSITY FOR RESIDUES 1-77

spinqualitylabelsall models 1vcc, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1vcc is a 1 chain structure with sequence from Vaccw. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Activity: DNA topoisomerase, with EC number 5.99.1.2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [TOP1_VACCW] Releases the supercoiling and torsional tension of DNA introduced during the DNA replication and transcription by transiently cleaving and rejoining one strand of the DNA duplex. Introduces a single-strand break via transesterification at the specific target site 5'-[CT]CCTTp site in duplex DNA. The scissile phosphodiester is attacked by the catalytic tyrosine of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-enzyme intermediate and the expulsion of a 5'-OH DNA strand. The free DNA strand then undergoes passage around the unbroken strand thus removing DNA supercoils. Finally, in the religation step, the DNA 5'-OH attacks the covalent intermediate to expel the active-site tyrosine and restore the DNA phosphodiester backbone. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed BACKGROUND: Vaccinia virus, a cytoplasmically-replicating poxvirus, encodes a type I DNA topoisomerase that is biochemically similar to eukaryotic-like DNA topoisomerases I, and which has been widely studied as a model topoisomerase. It is the smallest topoisomerase known and is unusual in that it is resistant to the potent chemotherapeutic agent camptothecin. RESULTS: The crystal structure of a 9 kDa amino-terminal fragment of vaccinia virus DNA topoisomerase I has been determined at 1.6 A resolution. The fragment forms a five-stranded, antiparallel beta-sheet with two short alpha-helices and connecting loops. Residues that are conserved between all eukaryotic-like type I topoisomerases are not clustered in particular regions of the structure. CONCLUSIONS: This is the first atomic structure of any region of a eukaryotic-like DNA topoisomerase I. It has provided insights into the structural bases of the phenotypes of some single-site mutants of the intact topoisomerase. The structure has enabled us to study the interactions within a well-folded protein fragment and the camptothecin resistance of the viral topoisomerase. Crystal structure of the amino-terminal fragment of vaccinia virus DNA topoisomerase I at 1.6 A resolution.,Sharma A, Hanai R, Mondragon A Structure. 1994 Aug 15;2(8):767-77. PMID:7994576 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Topoisomerase

Proteopedia Page Contributors and Editors (what is this?)

OCA