Isolation and characterization of a novel conus peptide with apparent antinociceptive activity.
Cone snails are tropical marine mollusks that envenomate prey with a complex mixture of neuropharmacologically active compounds. We report the discovery and biochemical characterization of a structurally unique peptide isolated from the venom of Conus marmoreus. The new peptide, mr10a, potently increased withdrawal latency in a hot plate assay (a test of analgesia) at intrathecal doses that do not produce motor impairment as measured by rotarod test. The sequence of mr10a is NGVCCGYKLCHOC, where O is 4-trans-hydroxyproline. This sequence is highly divergent from all other known conotoxins. Analysis of a cDNA clone encoding the toxin, however, indicates that it is a member of the recently described T-superfamily. Total chemical synthesis of the three possible disulfide arrangements of mr10a was achieved, and elution studies indicate that the native form has a disulfide connectivity of Cys1-Cys4 and Cys2-Cys3. This disulfide linkage is unprecedented among conotoxins and defines a new family of Conus peptides.
McIntosh
J M
JM
Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah 84112, Cognetix, Inc., Salt Lake City, Utah, 84108, USA. mcintosh@biology.utah.edu
Corpuz
G O
GO
Layer
R T
RT
Garrett
J E
JE
Wagstaff
J D
JD
Bulaj
G
G
Vyazovkina
A
A
Yoshikami
D
D
Cruz
L J
LJ
Olivera
B M
BM
D000595:Amino Acid Sequence; D000700:Analgesics / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D020916:Conotoxins / Q000737:chemistry* / Q000494:pharmacology*; D004558:Electric Stimulation; D006358:Hot Temperature; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D010146:Pain / Q000503:physiopathology* / Q000517:prevention & control; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D021122:Protein Subunits; D011894:Rana pipiens; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000187:drug effects; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013127:Spinal Nerves / Q000187:drug effects / Q000502:physiology*; D014982:Xenopus laevis
D000700:Analgesics; D020916:Conotoxins; D010446:Peptide Fragments; D021122:Protein Subunits; D011978:Receptors, Nicotinic; D011994:Recombinant Proteins