Table 1.

Modulation of ErmC′ N-methyltransferase activity by peptides derived from phage display

Peptide (50 μg/ml)acpm (avg)Normalized %SD (%)
Complete (with ErmC′)5,158100
 + peptide 1, TARVVLK2,5776139
 + peptide 2, YIGVETE1,5483311
 + peptide 3, SGFLGLQ2,0784828
 + peptide 4, LWVMKST2,3095225
 + peptide 5, YEVMMWG2,359487
 + peptide 6, LSGVIAT1,4883524
  With resistant rRNA6571610
 No enzyme467118
Complete (with ErmC′)3,464100
 + rnd 5, WGEMMYV3,67110526
 + rnd 6, ATSVILG3,3789816
  • a Peptides obtained by combinatorial phage display were chemically synthesized as the N-acetyl and C-amide, and their effect on methylation of 23S rRNA catalyzed by ErmC′ was tested in triplicate as described in Materials and Methods. Resistant rRNA was methylated in vivo, purified by phenol-extraction from ribosomes, and used as a negative control. The sequences of peptides rnd 5 and rnd 6 were based on a randomization of the sequences of peptides 5 and 6, respectively, and were used as negative controls. Two sets of experiments were performed. To facilitate comparison, the data were normalized, setting the unsupplemented complete reaction data to 100%.