Poster abstracts

Poster number 11 submitted by Anne-Cecile Duc

Binding studies of a peptide with the A-site rRNA

Anne-Cecile E. Duc (Wayne State University), Mei Li (Wayne State University), Christine S. Chow (Wayne State University)

Abstract:
The increasing number of resistant bacteria to the existing antibiotic panoply is of great concern. Among these antibiotics, almost half are interfering with the protein synthesis machinery, whose core is the ribosome. Within its two subunits, the ribosome harbors several sites targeted by antibiotics, one of them being the A site. The A-site rRNA, located on helix 44 of the small subunit 16 S rRNA, is involved in the universal decoding phenomenon, and therefore offers few possibilities for mutations. In our research, phage display was previously used to identify a peptide that binds to the 27-nucleotide A-site RNA model. The identification of the key amino acids in the binding to the RNA was determined by performing single and double alanine screening. The variant peptides were analyzed using biophysical methods such as electrospray-ionization mass spectrometry, enzymatic footprinting and circular dichroism. These studies give some insights about the affinity and specificity of the peptide variants with the E. coli A-site RNA. Understanding these interactions will lead us to modify the peptide to enhance its affinity and specificity, therefore its activity.

References:
Steitz. T. A., On the structural basis of peptide-bond formation and antibiotic resistance from atomic structures of the large ribosomal subunit. FEBS Letters 2005, 579, (4), 955-958
Fourmy D., R. M. I., Blanchard S. C., Puglisi J. D., Structure of the A Site of Escherichia coli 16 S Ribosomal RNA Complexed with an Aminoglycoside Antibiotic. Science 1996, 274, (5291), 1367-1371

Keywords: RNA, peptide, Ribosome