KOZYAVKIN, SA and KRAH, R and GELLERT, M and STETTER, KO and LAKE, JA and SLESAREV, AI (1994) A REVERSE GYRASE WITH AN UNUSUAL STRUCTURE - A TYPE-I DNA TOPOISOMERASE FROM THE HYPERTHERMOPHILE METHANOPYRUS-KANDLERI IS A 2-SUBUNIT PROTEIN. JOURNAL OF BIOLOGICAL CHEMISTRY, 269 (15). pp. 11081-11089. ISSN 0021-9258, 1083-351X
Full text not available from this repository.Abstract
Reverse gyrase, an ATP-dependent topoisomerase that positively supercoils DNA, has been purified to near-homogeneity from the hyperthermophile Methanopyrus kandleri. It migrates on SDS-polyacrylamide gel electrophoresis as two principal bands with apparent molecular masses of 150 and 50 kDa. Both proteins remain associated throughout all chromatographic steps. Transfer of a radioactive phosphate from DNA to the 50-kDa protein and gel retardation experiments indicate that this protein forms the covalent complex with DNA. A blot overlay assay identifies the 150-kDa protein as the potential ATPase. This is the first evidence that a reverse gyrase can be a topoisomerase consisting of two protomers. In analogy with the DNA gyrase A subunit (DNA breakage and reunion activity) and the B subunit (ATPase), the 50- and 150-kDa components of Mka reverse gyrase have been designated the A and B subunits, respectively. Methanopyrus reverse gyrase changes DNA linking number in steps of one and its A subunit covalently binds to the 5'-DNA phosphoryl group. It nicks DNA at sites that predominantly have a cytosine at the -4-position. The same rule was derived previously for monomeric reverse gyrase from sulfur-metabolizing hyperthermophiles and for topoisomerase I from mesophilic bacteria. Based on these results, Mka reverse gyrase is classified as belonging to group A of type I topoisomerases. The structural diversity of type I group A topoisomerases parallels the diversity of type II enzymes and suggests the evolution of an essential function by gene fusion.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | GTP-BINDING PROTEIN; ESCHERICHIA-COLI; DESULFUROCOCCUS-AMYLOLYTICUS; SUPERHELICAL TURNS; CLEAVAGE REACTION; SUPERCOILED DNA; ATPASE ACTIVITY; NALIDIXIC-ACID; GENE-PRODUCT; DUPLEX DNA; |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:40 |
| URI: | https://pred.uni-regensburg.de/id/eprint/53321 |
Actions (login required)
 |
View Item |
