Purification, Structure and Properties of Escherichia coli tRNA Pseudouridine Synthase 1.
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).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1987
- Accession Number
- ADA183886
Entities
People
- Christopher C. Marvel
- Edward E. Penhoet
- Harold O. Kammen
- Larry Hardy
Organizations
- University of California