Protection of Mucuna pruriens seeds against Echis carinatus venom is exerted through a multiform glycoprotein whose oligosaccharide chains are functional in this role.
In a previous paper we demonstrated that extracts of Mucuna pruriens seeds (MPE) protect mice against Echis carinatus venom (EV) by an immunological mechanism. In this paper we demonstrate that the MPE immunogen generating the antibody that cross-reacts with the venom proteins is a multiform glycoprotein (gpMuc) whose immunogenic properties mainly reside in its glycan-chains. The glycoprotein was purified from the protein extract of M. pruriens seeds using Concanavalin A affinity chromatography. Using 2-D gel electrophoresis it separated into seven isoforms having MWs in the range from 20.3 to 28.7 kDa and pIs from 4.8 to 6.5. N-terminal sequencing of these spots revealed close similarity since all of them contained the consensus sequence DDREPV-DT found in soybean Kunitz-type trypsin inhibitor. We suggest that gpMuc contains both N- and O-glycans. Mild alkaline treatment but not PNGase F led to loss of reactivity, indicating that O-glycans are probably involved in the antigenicity of gpMuc.
Guerranti
Roberto
R
Dipartimento di Medicina Interna, Scienze Endocrino-metaboliche e Biochimica, Università di Siena, Via A. Moro 2, 53100 Siena, Italy. guerranti@unisi.it
Aguiyi
John C
JC
Ogueli
Ifeanyi G
IG
Onorati
Gianni
G
Neri
Stefano
S
Rosati
Floriana
F
Del Buono
Francesca
F
Lampariello
Raffaella
R
Pagani
Roberto
R
Marinello
Enrico
E
D000595:Amino Acid Sequence; D010450:Endopeptidases / Q000737:chemistry / Q000276:immunology*; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D031299:Mucuna; D009844:Oligosaccharides / Q000737:chemistry / Q000276:immunology; D010936:Plant Extracts / Q000378:metabolism*; D020011:Protective Agents / Q000737:chemistry; D020033:Protein Isoforms / Q000737:chemistry / Q000276:immunology; D012639:Seeds / Q000737:chemistry* / Q000276:immunology*; D014757:Viper Venoms / Q000737:chemistry / Q000276:immunology
D006023:Glycoproteins; D009844:Oligosaccharides; D010936:Plant Extracts; D020011:Protective Agents; D020033:Protein Isoforms; D014757:Viper Venoms; D010450:Endopeptidases; C020097:ecarin