title: Crystal structure and evolution of a transfer RNA splicing enzyme.
abstract: The splicing of transfer RNA precursors is similar in Eucarya and Archaea. In both kingdoms an endonuclease recognizes the splice sites and releases the intron, but the mechanism of splice site recognition is different in each kingdom. The crystal structure of the endonuclease from the archaeon Methanococcus jannaschii was determined to a resolution of 2.3 angstroms. The structure indicates that the cleavage reaction is similar to that of ribonuclease A and the arrangement of the active sites is conserved between the archaeal and eucaryal enzymes. These results suggest an evolutionary pathway for splice site recognition.
authors.affiliation: Division of Biology, Mail Code 147-75, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.forename: C R
authors.initials: CR
authors.lastname: Trotta
authors.forename: J
authors.initials: J
authors.lastname: Abelson
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D019281:Dimerization; D004722:Endoribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D016325:HIV Long Terminal Repeat; D006860:Hydrogen Bonding; D017017:Methanococcus / Q000201:enzymology* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012322:RNA Precursors / Q000737:chemistry / Q000378:metabolism; D012326:RNA Splicing; D019642:RNA, Archaeal / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology
chemical_list: D012322:RNA Precursors; D019642:RNA, Archaeal; D004722:Endoribonucleases; C051012:splicing endonuclease