title: Evidence that the lizard helospectin peptides are O-glycosylated.
abstract: Six forms of helospectin (a vasoactive intestinal peptide analogue) were purified from the venom of the Heloderma horridum lizard. Their identification was performed by combining sequencing by automated Edman degradation and electrospray mass spectrometry analysis on the complete peptides and their tryptic fragments. The products resulting from the action of an O-glycosidase were also analysed. Two forms were identified as the previously named Hs1 and Hs2 of 38 and 37 amino-acid residues, respectively. Two forms corresponded to Hs1 and Hs2 O-glycosylated by a N-acetylhexosamine-hexose motif attached to the Ser32 residue. Two other forms were not completely characterized but might correspond to the O-glycosylated forms bearing a phosphate or a sulfate group. The glycosylation did not affect the capacity of the helospectins to recognize and to activate the human and the rat VPAC1 and VPAC2 receptors.
authors.affiliation: Department of Biochemistry and Nutrition, Faculty of Medicine, Université Libre de Bruxelles, Belgium.
authors.forename: M C
authors.initials: MC
authors.lastname: Vandermeers-Piret
authors.forename: A
authors.initials: A
authors.lastname: Vandermeers
authors.forename: P
authors.initials: P
authors.lastname: Gourlet
authors.forename: M H
authors.initials: MH
authors.lastname: Ali
authors.forename: M
authors.initials: M
authors.lastname: Waelbroeck
authors.forename: P
authors.initials: P
authors.lastname: Robberecht
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000595:Amino Acid Sequence; D000664:Amphibian Venoms / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006031:Glycosylation; D006801:Humans; D020128:Inhibitory Concentration 50; D036341:Intercellular Signaling Peptides and Proteins; D008116:Lizards / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D051381:Rats; D018005:Receptors, Vasoactive Intestinal Peptide / Q000378:metabolism; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014357:Trypsin / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000664:Amphibian Venoms; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D018005:Receptors, Vasoactive Intestinal Peptide; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D011994:Recombinant Proteins; C091796:helospectin; D014660:Vasoactive Intestinal Peptide; C040442:heliodermin; D014357:Trypsin; D000262:Adenylyl Cyclases