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

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

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 not free of limitations, certainly, new approaches are needed and, therefore, we explore here, the feasibility of using 13C chemical shifts of different nuclei to detect glycosylation of protein residues by monitoring the deviation of the 13C chemical shifts from the expected (mean) experimental value of the non-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 our attention on the Δ values upon glycosylation for some selected 13C nuclei 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 monitoring the 13Cβ nucleus of Ser and Thr and the 13Cg nucleus of Asn, can be used to detect the most commonly seen O-and N-glycosylations of these residues, except for the type of monosaccharide linked to Ser. Because chemical-shift is a local property, the proposed detection method should be useful for any state of the protein, i.e.,even for intrinsically disordered proteins.