title: Reverse gyrase: an unusual DNA manipulator of hyperthermophilic organisms.
abstract: Reverse gyrase is the only DNA topoisomerase capable of introducing positive supercoiling into DNA molecules. This unique activity reflects a distinctive arrangement of the protein, which is composed of a topoisomerase IA module fused to a domain containing sequence motives typical of helicases; however, reverse gyrase works neither like a canonical topoisomerase IA nor like a helicase. Extensive genomic analysis has shown that reverse gyrase is present in all organisms living above 70 degrees C and in some of those living at 60- 70 degrees C, but is invariably absent in organisms living at mesophilic temperatures. For its peculiar distribution and biochemical activity, the enzyme has been suggested to play a role in maintenance of genome stability at high temperature. We review here recent phylogenetic, biochemical and structural data on reverse gyrase and discuss the possible role of this enzyme in the biology of hyperthermophilic organisms.
authors.affiliation: Institute of Protein Biochemistry, Consiglio Nazionale delle Ricerche, Naples, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: D'Amaro
authors.forename: Mosè
authors.initials: M
authors.lastname: Rossi
authors.forename: Maria
authors.initials: M
authors.lastname: Ciaramella
mesh_terms: D020816:Amino Acid Motifs; D001105:Archaea / Q000201:enzymology*; D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism*; D004264:DNA Topoisomerases, Type I / Q000737:chemistry / Q000378:metabolism*; D004278:DNA, Superhelical / Q000378:metabolism*; D020745:Genome, Archaeal / Q000502:physiology*; D042822:Genomic Instability / Q000502:physiology*; D006358:Hot Temperature; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D019843:Archaeal Proteins; D004278:DNA, Superhelical; C041813:DNA reverse gyrase; D004264:DNA Topoisomerases, Type I