Characterization and crystal structure of the type IIG restriction endonuclease RM.BpuSI.

Publication Type:

Journal Article

Source:

Nucleic acids research, Volume 39, Issue 18, p.8223-36 (2011)

Keywords:

2011, Amino Acid Sequence, Bacillus, Basic Sciences Division, CATALYTIC DOMAIN, Center-Authored Paper, Crystallography, X-Ray, Deoxyribonucleases, Type II Site-Specific, DNA Cleavage, DNA Modification Methylases, Kinetics, Models, Molecular, Molecular Sequence Data, Mutagenesis, Site-Directed, Protein Structure, Tertiary, September 2011, Sequence Alignment

Abstract:

A type IIG restriction endonuclease, RM.BpuSI from Bacillus pumilus, has been characterized and its X-ray crystal structure determined at 2.35Å resolution. The enzyme is comprised of an array of 5-folded domains that couple the enzyme's N-terminal endonuclease domain to its C-terminal target recognition and methylation activities. The REase domain contains a PD-x(15)-ExK motif, is closely superimposable against the FokI endonuclease domain, and coordinates a single metal ion. A helical bundle domain connects the endonuclease and methyltransferase (MTase) domains. The MTase domain is similar to the N6-adenine MTase M.TaqI, while the target recognition domain (TRD or specificity domain) resembles a truncated S subunit of Type I R-M system. A final structural domain, that may form additional DNA contacts, interrupts the TRD. DNA binding and cleavage must involve large movements of the endonuclease and TRD domains, that are probably tightly coordinated and coupled to target site methylation status.