Mar. Drugs 2013, 11, 623-642; doi:10.3390/md11030623 OPEN ACCESS Marine Drugs ISSN 1660-3397 www.mdpi.com/journal/marinedrugs Review Glycosylation of Conotoxins Gerrit J. Gerwig 1, Henry G. Hocking 1, Reto Stöcklin 2, Johannis P. Kamerling 1 and Rolf Boelens 1,* 1 NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; E-Mails:
[email protected] (G.J.G.);
[email protected] (H.G.H.);
[email protected] (J.P.K.) 2 Atheris Laboratories, Case postale 314, CH-1233 Bernex-Geneva, Switzerland; E-Mail:
[email protected] * Author to whom correspondence should be addressed; E-Mail:
[email protected]; Tel.: +31-30-253-2652; Fax: +31-30-253-7623. Received: 14 December 2012; in revised form: 25 January 2013 / Accepted: 6 February 2013 / Published: 1 March 2013 Abstract: Conotoxins are small peptides present in the venom of cone snails. The snail uses this venom to paralyze and capture prey. The constituent conopeptides display a high level of chemical diversity and are of particular interest for scientists as tools employed in neurological studies and for drug development, because they target with exquisite specificity membrane receptors, transporters, and various ion channels in the nervous system. However, these peptides are known to contain a high frequency and variability of post-translational modifications—including sometimes O-glycosylation—which are of importance for biological activity. The potential application of specific conotoxins as neuropharmalogical agents and chemical probes requires a full characterization of the relevant peptides, including the structure of the carbohydrate part.