Detection of glycosylation of protein residues by monitoring 13C chemical-shift changes

VILA JORGE A.; GARAY PABLO G.; SCHERAGA HAROLD A.; MARTIN OSVALDO O.

Villa General Belgrano

Congreso; GlycoAr 2016; 2016

p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left; }p.western { font-family: "Liberation Serif",serif; font-size: 12pt; }p.cjk { font-family: "Droid Sans Fallback"; font-size: 12pt; }p.ctl { font-family: "FreeSans"; font-size: 12pt; }Post-translationalmodifications of proteins expand the diversity of the proteome byseveral orders of magnitude and have a profound effect on severalbiological processes. Their detection by experimental methods is notfree of limitations, certainly, new approaches are needed and,therefore, we explore here, the feasibility of using 13Cchemical shifts of different nuclei to detect glycosylation ofprotein residues by monitoring the deviation of the 13Cchemical shifts from the expected (mean) experimental value of thenon-modified residue (Δ value). We use this approach to select themost suitable 13C-nucleus,with which to determine the commonly glycosylation seen in serine(Ser), asparagine (Asn) and threonine (Thr). By focusing ourattention on the Δ values upon glycosylation for some selected13Cnuclei of the residue side-chain, we will be able to determinewhether, first, the Δ-values can be used to determine glycosylationand, second, the type of glycosylated residue. Ours results showsthat monitoringthe 13Cβnucleus of Ser and Thr and the 13Cgnucleus of Asn, can be used to detect the most commonly seen O-and N-glycosylationsof these residues, except for the type of monosaccharide linked toSer. Because chemical-shift is a local property, the proposeddetection method should be useful for any state of the protein, i.e.,even for intrinsically disordered proteins.