Accession Number : ADA183886

Title :   Purification, Structure and Properties of Escherichia coli tRNA Pseudouridine Synthase 1.

Descriptive Note : Summary rept. 1 Oct 85-30 Sep 87,

Corporate Author : CALIFORNIA UNIV OAKLAND NAVAL BIOSCIENCES LAB

Personal Author(s) : Kammen,Harold O ; Marvel,Christopher C ; Hardy,Larry ; Penhoet,Edward E

PDF Url : ADA183886

Report Date : Jan 1987

Pagination or Media Count : 43

Abstract : The RNA modification enzyme, tRNA pseudourine synthase I (PSUI) has been isolated in 95% purity from an Escherichia coli strain harboring multicopy plasmid with a 2.3kb insert for the hisT operon. Its molecular size, amino acid composition and N-terminal sequence correspond to those predicted by the structure and expression of the hisT gene. Enzyme activity, as measured by a 3H release assay, is unaffected by pretreatment if PSUI with micrococcal nuclease and is optimized by the addition of a monovalent cation and thiol reductant. The activity is inhibited by all tRNA species tested, including substrates, modified tRNAs, non substrates and non substrates tRNAs and does not require a monovalent cation. Our finding are consistent with a multi-step mechanism whereby PSUI first binds non-specifically, then forms transient covalent adducts with tRNA substrates. Keywords: Charts; Graphs; Tables(Data).

Descriptors :   *ESCHERICHIA COLI, *SYNTHASES, *GENETICS, *BIOCHEMISTRY, ACIDS, AMINO ACIDS, GRAPHS, CATIONS, VALENCE, NUCLEASE, CHROMOSOMES, PURIFICATION, ENZYMES, MOLECULES, SUBSTRATES, OPTIMIZATION, RIBONUCLEIC ACIDS, TABLES(DATA), CHARTS, MOLECULAR STRUCTURE, BIOASSAY

Subject Categories : Genetic Engineering and Molecular Biology
      Biochemistry
      Microbiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE