title: Detection of vitamin K-dependent proteins in venoms with a monoclonal antibody specific for gamma-carboxyglutamic acid.
abstract: gamma-Carboxyglutamic acid (Gla) is an unusual amino acid that is synthesized post-translationally from glutamate in a vitamin K-dependent reaction. The dicarboxylic side chain of Gla chelates Ca(2+), a property important for the biological activity of vitamin K-dependent proteins. To date, Gla-containing polypeptides have been identified in venom from two groups of organisms: elapid snakes, and snails of the genus Conus. In certain elapid snakes, a gamma-carboxylated coagulation factor Xa-like protein is a component of the venom whereas cone snails utilize Gla in a range of peptide neurotoxins. Using a monoclonal antibody that specifically recognizes Gla residues, venom samples from various organisms were screened by western blotting and immunofluorescence assays. Amino acid analyses were also performed on most samples. A survey of 21 snake species from 12 genera detected gamma-carboxylated polypeptides only in venom of snakes from the elapid subfamily Acanthophiinae. Gla-containing polypeptides were also observed in cone snail venom but not in venom or toxic salivary secretions from several other organisms. The Gla-specific antibody used here provides a simple immunochemical means to detect gamma-carboxylated polypeptides in venom and may allow new species to be identified that utilize Gla in the biosynthesis of toxic polypeptides.
authors.affiliation: Department of Clinical Chemistry, Lund University, University Hospital, Malmö, S-205 02, Malmö, Sweden.
authors.forename: M A
authors.initials: MA
authors.lastname: Brown
authors.forename: B
authors.initials: B
authors.lastname: Hambe
authors.forename: B
authors.initials: B
authors.lastname: Furie
authors.forename: B C
authors.initials: BC
authors.lastname: Furie
authors.forename: J
authors.initials: J
authors.lastname: Stenflo
authors.forename: L M
authors.initials: LM
authors.lastname: Stenberg
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000032:analysis* / Q000276:immunology / Q000494:pharmacology; D000664:Amphibian Venoms / Q000737:chemistry*; D000818:Animals; D000911:Antibodies, Monoclonal; D001001:Anura; D001681:Biological Assay / Q000379:methods; D001798:Blood Proteins / Q000378:metabolism; D015153:Blotting, Western; D004546:Elapid Venoms / Q000737:chemistry*; D015951:Factor Xa / Q000032:analysis / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D008978:Mollusk Venoms / Q000737:chemistry*; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D012469:Salivary Glands / Q000737:chemistry; D012908:Snails; D012911:Snakes; D014812:Vitamin K / Q000494:pharmacology*
chemical_list: D000664:Amphibian Venoms; D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D004546:Elapid Venoms; D008978:Mollusk Venoms; D010455:Peptides; D014812:Vitamin K; D015055:1-Carboxyglutamic Acid; D015951:Factor Xa