Citation

Ul-Hasan S, Burgess DM, Gajewiak J, Qing L, Hu H, Yandell M, Olivera BM, Bandyopadhyay PK. Toxicon 2013; 74: 215-224.

Affiliation

Department of Biology, 257 South 1400 East, Salt Lake City, UT 84112, USA.

Copyright

(Copyright © 2013, Elsevier Publishing)

DOI

10.1016/j.toxicon.2013.08.054

PMID

23994590

Abstract

Cone snails, genus Conus, are predatory marine snails that use venom to capture their prey. This venom contains a diverse array of peptide toxins, known as conotoxins, which undergo a diverse set of posttranslational modifications. Amidating enzymes modify peptides and proteins containing a C-terminal glycine residue, resulting in loss of the glycine residue and amidation of the preceding residue. A significant fraction of peptides present in the venom of cone snails contain C-terminal amidated residues, which are important for optimizing biological activity. This study describes the characterization of the amidating enzyme, peptidylglycine α-amidating monooxygenase (PAM), present in the venom duct of cone snails, Conus bullatus and Conus geographus. PAM is known to carry out two functions, peptidyl α-hydroxylating monooxygenase (PHM) and peptidylamido-glycolate lyase (PAL). In some animals, such as Drosophila melanogaster, these two functions are present in separate polypeptides, working as individual enzymes. In other animals, such as mammals and in Aplysia californica, PAM activity resides in a single, bifunctional polypeptide. Using specific oligonucleotide primers and reverse transcription-polymerase chain reaction we have identified and cloned from the venom duct cDNA library, a cDNA with 49% homology to PAM from Aplysia californica. We have determined that both the PHM and PAL activities are encoded in one mRNA polynucleotide in both Conus bullatus and Conus geographus. We have directly demonstrated enzymatic activity catalyzing the conversion of dansyl-YVG-COOH to dansyl-YV-NH2 in cloned cDNA expressed in Drosophila S2 cells.

Language: en