Pivotal role of a conserved histidine in Escherichia coli ribonuclease HI as proposed by X-ray crystallography.

ABSTRACT: The ribonuclease (RNase) H family of enzymes catalyze the specific cleavage of RNA strands of RNA/DNA hybrid duplexes and play an important role in DNA replication and repair. Since the first report of the crystal structure of RNase HI, its catalytic mechanisms, which require metal ions, have been discussed based on numerous structural and functional analyses, including X-ray crystallography. In contrast, the function of the conserved histidine residue (His124 in Escherichia coli) in the flexible loop around the active site remains poorly understood, although an important role was suggested by NMR analyses. Here, novel high-resolution X-ray crystal structures of E. coli RNase HI are described, with a particular focus on the interactions of divalent cations with His124 oriented towards the

SUBMITTER: Liao Z 

PROVIDER: S-EPMC8900815 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature