title: Structure of bacteriophage T4 RNase H, a 5' to 3' RNA-DNA and DNA-DNA exonuclease with sequence similarity to the RAD2 family of eukaryotic proteins.
abstract: Bacteriophage T4 RNase H is a 5' to 3' exonuclease that removes RNA primers from the lagging strand of the DNA replication fork and is a member of the RAD2 family of eukaryotic and prokaryotic replication and repair nucleases. The crystal structure of the full-length native form of T4 RNase H has been solved at 2.06 angstroms resolution in the presence of Mg2+ but in the absence of nucleic acids. The most conserved residues are clustered together in a large cleft with two Mg2+ in the proposed active site. This structure suggests the way in which the widely separated conserved regions in the larger nucleotide excision repair proteins, such as human XPG, could assemble into a structure like that of the smaller replication nucleases.
authors.affiliation: Laboratory of Structural Biology Research, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892-2755, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Mueser
authors.forename: N G
authors.initials: NG
authors.lastname: Nossal
authors.forename: C C
authors.initials: CC
authors.lastname: Hyde
mesh_terms: D017122:Bacteriophage T4 / Q000737:chemistry / Q000201:enzymology*; D001665:Binding Sites / Q000502:physiology; D003461:Crystallography; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry; D004706:Endodeoxyribonucleases / Q000737:chemistry; D005092:Exonucleases / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D008274:Magnesium / Q000737:chemistry; D008670:Metals / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry; D016914:Ribonuclease H / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D019914:Taq Polymerase
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D008670:Metals; D029701:Saccharomyces cerevisiae Proteins; C073998:RAD2 protein, S cerevisiae; D012313:RNA; D004247:DNA; D019914:Taq Polymerase; D012194:RNA-Directed DNA Polymerase; D004259:DNA-Directed DNA Polymerase; D004706:Endodeoxyribonucleases; D005092:Exonucleases; D016914:Ribonuclease H; D008274:Magnesium