title: Self-catalysed affinity labeling of Q beta replicase.
abstract: The spatial neighbourhood of the active center of Q beta replicase can be selectively modified by the method of self-catalysed affinity labeling. In the template-directed, mainly intramolecular enzymatic catalysis, the product [32P]GpG becomes specifically attached to the beta subunit. Using limited digestion of the radioactively labeled polypeptide by cyanogen bromide or N-chlorosuccinimide, we have mapped the attachment site to the region of subunit beta between Trp93 and Met130. Under our reaction conditions, Lys95 is the amino acid most likely to be modified, suggesting that Lys95 lies near the nucleotide binding site in the active center.
authors.affiliation: Institut für Biochemie, Ludwig-Maximilians-Universität, München, Federal Republic of Germany.
authors.forename: A J
authors.initials: AJ
authors.lastname: Lindner
authors.forename: S J
authors.initials: SJ
authors.lastname: Glaser
authors.forename: C K
authors.initials: CK
authors.lastname: Biebricher
authors.forename: G R
authors.initials: GR
authors.lastname: Hartmann
mesh_terms: D000345:Affinity Labels; D001483:Base Sequence; D002384:Catalysis; D002855:Chromatography, Thin Layer; D003488:Cyanogen Bromide / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D006160:Guanosine Triphosphate / Q000737:chemistry; D008969:Molecular Sequence Data; D010777:Photochemistry; D011777:Q beta Replicase / Q000737:chemistry*; D013388:Succinimides / Q000737:chemistry
chemical_list: D000345:Affinity Labels; D013388:Succinimides; C015752:N-chlorosuccinimide; D006160:Guanosine Triphosphate; D011777:Q beta Replicase; D003488:Cyanogen Bromide