title: Crystal structure of the Escherichia coli dcm very-short-patch DNA repair endonuclease bound to its reaction product-site in a DNA superhelix.
abstract: Very-short-patch repair (Vsr) enzymes occur in a variety of bacteria, where they initiate nucleotide excision repair of G:T mismatches arising by deamination of 5-methyl-cytosines in specific regulatory sequences. We have now determined the structure of the archetypal dcm-Vsr endonuclease from Escherichia coli bound to the cleaved authentic hemi-deaminated/hemi-methylated dcm sequence 5'-C-OH-3' 5'-p-T-p-A-p-G-p-G-3'/3'-G-p-G-p-T-p(Me5)C-p-C formed by self-assembly of a 12mer oligonucleotide into a continuous nicked DNA superhelix. The structure reveals the presence of a Hoogsteen base pair within the deaminated recognition sequence and the substantial distortions of the DNA that accompany Vsr binding to product sites.
authors.affiliation: Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Bunting
authors.forename: S Mark
authors.initials: SM
authors.lastname: Roe
authors.forename: Anthony
authors.initials: A
authors.lastname: Headley
authors.forename: Tom
authors.initials: T
authors.lastname: Brown
authors.forename: Renos
authors.initials: R
authors.lastname: Savva
authors.forename: Laurence H
authors.initials: LH
authors.lastname: Pearl
mesh_terms: D020137:Base Pair Mismatch / Q000235:genetics; D001483:Base Sequence; D018360:Crystallography, X-Ray; D004260:DNA Repair; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding
chemical_list: D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D009841:Oligonucleotides; D004706:Endodeoxyribonucleases; C071421:vsr endonuclease