title: L16, a bifunctional ribosomal protein and the enhancing effect of L6 and L11.
abstract: L16 exhibits both peptide bond and transesterification activities when reconstituted into 2 M LiCl core particles. L6 and L11, when reconstituted in a similar manner in the absence of L16, manifest significant transesterification activity. Both L6 and L11 enhance the transesterification activity of L16; L11 being more active than L6 in this respect. However, both L6 and L11 have minimal effect on peptide bond formation when reconstituted with L16 at concentrations more than 2.5 M equivalents. Both L6 and L11 exhibit a differential effect on transesterification. The affinity-labelling agents, like PhCH2SO2F, diisopropylfluorophosphate and ethoxyformic anhydride, have been used to explore the role of residues in peptide bond formation and transesterification. It is proposed that the Ser-Phe combination present in L16, L11 and L6 is involved in transesterification in addition to the single histidine in L16. The single histidine in L16 appears to be important in the catalysis of peptide bond formation and transesterification.
mesh_terms: D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004047:Diethyl Pyrocarbonate; D007531:Isoflurophate; D010458:Peptidyl Transferases; D010664:Phenylmethylsulfonyl Fluoride; D012269:Ribosomal Proteins / Q000494:pharmacology*
chemical_list: D003432:Cross-Linking Reagents; D012269:Ribosomal Proteins; C027624:ribosomal protein L11; C027937:ribosomal protein L16; C031249:ribosomal protein L6; D007531:Isoflurophate; D010664:Phenylmethylsulfonyl Fluoride; D010458:Peptidyl Transferases; D004047:Diethyl Pyrocarbonate