From Proteopediaproteopedia link
ARCHAEOGLOBUS FULGIDUS REVERSE GYRASE COMPLEXED WITH ADPNP
[RGYR_ARCFU] Modifies the topological state of DNA by introducing positive supercoils in an ATP-dependent process. It cleaves transiently a single DNA strand and remains covalently bound to the 5' DNA end through a tyrosine residue. May be involved in rewinding the DNA strands in the regions of the chromosome that have opened up to allow transcription or replication.
Publication Abstract from PubMed
Reverse gyrase is the only topoisomerase known to positively supercoil DNA. The protein appears to be unique to hyperthermophiles, where its activity is believed to protect the genome from denaturation. The 120 kDa enzyme is the only member of the type I topoisomerase family that requires ATP, which is bound and hydrolysed by a helicase-like domain. We have determined the crystal structure of reverse gyrase from Archaeoglobus fulgidus in the presence and absence of nucleotide cofactor. The structure provides the first view of an intact supercoiling enzyme, explains mechanistic differences from other type I topoisomerases and suggests a model for how the two domains of the protein cooperate to positively supercoil DNA. Coordinates have been deposited in the Protein Data Bank under accession codes 1GKU and 1GL9.
Crystal structure of reverse gyrase: insights into the positive supercoiling of DNA.,Rodriguez AC, Stock D EMBO J. 2002 Feb 1;21(3):418-26. PMID:11823434
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.