title: Fluorescence properties of a tryptophan residue in an aromatic core of the protein subunit of ribonuclease P from Escherichia coli.
abstract: Escherichia coli ribonuclease P (RNase P), a ribonucleoprotein complex which primarily functions in tRNA biosynthesis, is composed of a catalytic RNA subunit, M1 RNA, and a protein cofactor, C5 protein. The fluorescence emission spectrum of the single tryptophan residue-containing C5 protein exhibits maxima at 318 nm and 332 nm. Based on a comparison of the emission spectra of wild-type C5 protein and some of its mutant derivatives, we have determined that the 318 nm maximum could be the result of a complex formed in the excited state as a result of hydrophobic interactions between Trp109, Phe18 and Phe73. The analogous tryptophan fluorescence emission spectra of wild-type C5 protein and the barstar mutant W38F/W44F, taken together with the detailed structural information available for barstar, provide a possible explanation for the unusual emission spectrum of C5 protein.
authors.affiliation: Department of Biology, Yale University, New Haven, CT 06520-8103, USA.
authors.forename: V
authors.initials: V
authors.lastname: Gopalan
authors.forename: R
authors.initials: R
authors.lastname: Golbik
authors.forename: G
authors.initials: G
authors.lastname: Schreiber
authors.forename: A R
authors.initials: AR
authors.lastname: Fersht
authors.forename: S
authors.initials: S
authors.lastname: Altman
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D004722:Endoribonucleases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D008958:Models, Molecular; D009154:Mutation; D011489:Protein Denaturation; D016337:RNA, Catalytic / Q000037:antagonists & inhibitors / Q000737:chemistry*; D043262:Ribonuclease P; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry*; D014508:Urea
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D029968:Escherichia coli Proteins; D016337:RNA, Catalytic; C057438:barstar protein, Bacillus amyloliquefaciens; D014364:Tryptophan; D014508:Urea; D004722:Endoribonucleases; D043262:Ribonuclease P; C470865:ribonuclease P, E coli