The peptidyl transferase center (PTC), present in the domain V of 23S rRNA of bacteria can act as a general protein folding modulator. Any general function of a nucleic acid polymer (DNA or RNA) is always related to specific sequence/sequences. The ribosome mediated protein folding also involves a specific interaction between the nucleotides of peptidyl transferase center and the amino acids of an unfolded Protein. In this article the mechanism of rRNA assisted protein folding and its significance in the light of high resolution crystal structure of ribosome are discussed. (C) 2009 Elsevier Inc. All rights reserved.