Protein Family Models

This domain is found at the N-terminal end of Type I topoisomerase from Deinococcus radiodurans and similar bacterial sequences. This small-sized protein modify DNA topology by cleaving and resealing one strand of duplex DNA. This domain comprises three alpha-helices plus a five strand antiparallel beta-sheet [1]. It is found associated with Pfam:PF01028. Paper describing PDB structure 2f4q. [1]. 16368685. Crystal structure of a bacterial type IB DNA topoisomerase reveals a preassembled active site in the absence of DNA. Patel A, Shuman S, Mondragon A;. J Biol Chem. 2006;281:6030-6037. (from Pfam)

Date:

2024-10-16

Topoisomerase I promotes the relaxation of DNA superhelical tension by introducing a transient single-stranded break in duplex DNA and are vital for the processes of replication, transcription, and recombination [2]. [1]. 7770916. The mechanisms of DNA topoisomerases. Roca J;. Trends Biochem Sci 1995;20:156-160. [2]. 9488644. Crystal structures of human topoisomerase I in covalent and noncovalent complexes with DNA. Redinbo MR, Stewart L, Kuhn P, Champoux JJ, Hol WG;. Science 1998;279:1504-1513. (from Pfam)

Date:

2024-10-16

DNA topoisomerase IB is a monomeric enzyme that relaxes DNA supercoils by cleaving and resealing one strand of duplex DNA within a protein clamp that embraces an approximately 21 base-long DNA segment, it promotes the relaxation of both positive (overwound) and negative (underwound) DNA superhelical tension.

Date:

2018-02-09