title: An engineered ribonuclease preferring phosphorothioate RNA.
abstract: We used mutants of RNase T1 and the Rp isomer of a thiosubstituted substrate to determine stereospecific thioeffects on catalysis. The analysis reveals subtle structural and functional changes in the intermolecular transition state interactions. Tyr 38 contributes to catalysis through a hydrogen bond with the pro-Rp oxygen. Y38F RNase T1 prefers the Rp thiosubstituted analog over the natural phosphodiester substrate that is favored by the wild type enzyme.
authors.forename: S
authors.initials: S
authors.lastname: Loverix
authors.forename: A
authors.initials: A
authors.lastname: Winquist
authors.forename: R
authors.initials: R
authors.lastname: Strömberg
authors.forename: J
authors.initials: J
authors.lastname: Steyaert
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D002384:Catalysis; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000235:genetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D015202:Protein Engineering; D012313:RNA / Q000235:genetics*; D012260:Ribonucleases / Q000737:chemistry / Q000235:genetics*; D013379:Substrate Specificity / Q000235:genetics; D013873:Thionucleotides / Q000235:genetics*
chemical_list: D013873:Thionucleotides; C001774:guanosine 2',3'-cyclophosphorothioate; D012313:RNA; D012260:Ribonucleases; D006152:Cyclic GMP