title: Crystal structure of the phosphorolytic exoribonuclease RNase PH from Bacillus subtilis and implications for its quaternary structure and tRNA binding.
abstract: RNase PH is a member of the family of phosphorolytic 3' --> 5' exoribonucleases that also includes polynucleotide phosphorylase (PNPase). RNase PH is involved in the maturation of tRNA precursors and especially important for removal of nucleotide residues near the CCA acceptor end of the mature tRNAs. Wild-type and triple mutant R68Q-R73Q-R76Q RNase PH from Bacillus subtilis have been crystallized and the structures determined by X-ray diffraction to medium resolution. Wild-type and triple mutant RNase PH crystallize as a hexamer and dimer, respectively. The structures contain a rare left-handed beta alpha beta-motif in the N-terminal portion of the protein. This motif has also been identified in other enzymes involved in RNA metabolism. The RNase PH structure and active site can, despite low sequence similarity, be overlayed with the N-terminal core of the structure and active site of Streptomyces antibioticus PNPase. The surface of the RNase PH dimer fit the shape of a tRNA molecule.
authors.affiliation: Department of Biological Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
authors.forename: Lene S
authors.initials: LS
authors.lastname: Harlow
authors.forename: Anders
authors.initials: A
authors.lastname: Kadziola
authors.forename: Kaj Frank
authors.initials: KF
authors.lastname: Jensen
authors.forename: Sine
authors.initials: S
authors.lastname: Larsen
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry / Q000235:genetics; D001412:Bacillus subtilis / Q000201:enzymology*; D001665:Binding Sites / Q000235:genetics; D003460:Crystallization; D003461:Crystallography; D005095:Exoribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005973:Glutamine / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D020653:Peptide Elongation Factor G / Q000737:chemistry; D017354:Point Mutation / Q000235:genetics; D011117:Polyribonucleotide Nucleotidyltransferase / Q000737:chemistry / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D043262:Ribonuclease P / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013303:Streptomyces antibioticus / Q000737:chemistry / Q000235:genetics; D040681:Structural Homology, Protein; D017356:Synchrotrons
chemical_list: D020653:Peptide Elongation Factor G; D011994:Recombinant Proteins; D005973:Glutamine; D012343:RNA, Transfer; D001120:Arginine; C056502:ribonuclease PH; D011117:Polyribonucleotide Nucleotidyltransferase; D005095:Exoribonucleases; D043262:Ribonuclease P