title: The crystal structure of exonuclease RecJ bound to Mn2+ ion suggests how its characteristic motifs are involved in exonuclease activity.
abstract: RecJ, a 5' to 3' exonuclease specific for single-stranded DNA, functions in DNA repair and recombination systems. We determined the crystal structure of RecJ bound to Mn(2+) ion essential for its activity. RecJ has a novel fold in which two domains are interconnected by a long helix, forming a central groove. Mn(2+) is located on the wall of the groove and is coordinated by conserved residues characteristic of a family of phosphoesterases that includes RecJ proteins. The groove is composed of residues conserved among RecJ proteins and is positively charged. These findings and the narrow width of the groove indicate that the groove binds single- instead of double-stranded DNA.
authors.affiliation: Department of Biology, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamagata
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Kakuta
authors.forename: Ryoji
authors.initials: R
authors.lastname: Masui
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuyama
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D016963:Thermus thermophilus / Q000201:enzymology
chemical_list: D001426:Bacterial Proteins; D008345:Manganese; D004247:DNA; D005090:Exodeoxyribonucleases; C070765:recJ protein, Bacteria