title: MP-4 Contributes to Snake Venom Neutralization by Mucuna pruriens Seeds through an Indirect Antibody-mediated Mechanism.
abstract: Mortality due to snakebite is a serious public health problem, and available therapeutics are known to induce debilitating side effects. Traditional medicine suggests that seeds of Mucuna pruriens can provide protection against the effects of snakebite. Our aim is to identify the protein(s) that may be important for snake venom neutralization and elucidate its mechanism of action. To this end, we have identified and purified a protein from M. pruriens, which we have named MP-4. The full-length polypeptide sequence of MP-4 was obtained through N-terminal sequencing of peptide fragments. Sequence analysis suggested that the protein may belong to the Kunitz-type protease inhibitor family and therefore may potentially neutralize the proteases present in snake venom. Using various structural and biochemical tools coupled with in vivo assays, we are able to show that MP-4 does not afford direct protection against snake venom because it is actually a poor inhibitor of serine proteases. Further experiments showed that antibodies generated against MP-4 cross-react with the whole venom and provide protection to mice against Echis carinatus snake venom. This study shows that the MP-4 contributes significantly to the snake venom neutralization activity of M. pruriens seeds through an indirect antibody-mediated mechanism.
authors.affiliation: From the Structural Biology Unit, National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110 067, India, the Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, India, and.
authors.forename: Ashish
authors.initials: A
authors.lastname: Kumar
authors.affiliation: From the Structural Biology Unit, National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110 067, India.
authors.forename: Chitra
authors.initials: C
authors.lastname: Gupta
authors.affiliation: the Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, India, and deepak@rcb.res.in.
authors.forename: Deepak T
authors.identifier: http://orcid.org/0000-0002-0677-9444
authors.initials: DT
authors.lastname: Nair
authors.affiliation: From the Structural Biology Unit, National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110 067, India, the Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, India, and the International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110 067, India dinakar.salunke@gmail.com.
authors.forename: Dinakar M
authors.initials: DM
authors.lastname: Salunke
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057134:Antibodies, Neutralizing / Q000096:biosynthesis; D018360:Crystallography, X-Ray; D005260:Female; D006801:Humans; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008969:Molecular Sequence Data; D031299:Mucuna / Q000737:chemistry / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D010946:Plants, Medicinal; D012639:Seeds / Q000737:chemistry / Q000235:genetics; D012909:Snake Bites / Q000276:immunology / Q000628:therapy; D012910:Snake Venoms / Q000037:antagonists & inhibitors* / Q000276:immunology*; D014757:Viper Venoms / Q000037:antagonists & inhibitors / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D010940:Plant Proteins; D012910:Snake Venoms; D014757:Viper Venoms
keywords: antibody; crystal structure; humoral response; protease inhibitor; snake venom