Erwin Schrödinger Fellowship J 1994 Selecting the minimal ribosomal peptidyl transferase Norbert POLACEK
09.10.2000
The aim of the proposed project is to select for the minimal components of the ribosomal peptidyl transferase
center and to demonstrate catalytic activity of protein-free 23S rRNA. Peptide bond formation activity is integral to
the large ribosomal subunit, however the catalytic components of the active site have not been characterized in
molecular terms. There is accumulating evidence that the 23S rRNA of the large ribosomal subunit is an important
player and might function as a catalytic RNA enzyme (ribozyme). Comprehending how the ribosome works is at
the heart of molecular understanding of biology.
Decisive progress in elucidating the essential components of the peptidyl transferase center was recently achieved
in the Mankin lab. It was shown that Thermus aquaticus large ribosomal subunits that were treated with protein
extraction procedures remained catalytically active even though they only contained 23S rRNA, 5S rRNA and 8
ribosomal proteins. The aim of this project is to omit the remaining proteins one-by-one, and to select for 23S
rRNA variants that can compensate for the loss of the protein(s). To address this issue, the recently developed in
vitro reconstitution of large ribosomal subunits and the in vitro selection technique (SELEX) will be applied.