Campylobacter jejuni oligosaccharyl transferase PglB donor and acceptor specificity

BIOL 11

Mark M. Chen, markchen@mit.edu, Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 18-563, Cambridge, MA 02139 and Barbara Imperiali, imper@mit.edu, Department of Chemistry and Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139.
The gram-negative bacterium Campylobacter jejuni contains a general N-linked protein glycosylation pathway with notable similarities to the eukaryotic system. Central to this pathway is PglB, which transfers a preassembled oligosaccharide from a polyisoprenyl pyrophosphate carrier to the asparagine side chain of the conserved glycosylation site D/E-X1-N-X2-S/T, where X1 and X2 can be any amino acid other than proline. We probed both the acceptor and donor substrate specificity of PglB using a library of acceptor peptides and chemoenzymatically synthesized polyisoprenyl disaccharides. We have determined the optimal glycosylation acceptor sequence to be D-Q-N-A-T and we have found PglB to be non-specific towards the overall length of the polyisoprene although it has a distinct preference for the cis-double bond geometry and unsaturation at the alpha-isoprene position.
 

Frontiers in Chemical Biology
5:00 PM-7:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biological Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007