Amino acid sequence and biological activity of a gamma-conotoxin-like peptide from the worm-hunting snail Conus austini.
A novel 31-residue toxin, named as7a, was isolated and characterized from the venom of Conus austini, a vermivorous cone snail collected in the western Gulf of Mexico. The complete amino acid sequence, TCKQKGEGCSLDVgammaCCSSSCKPGGPLFDFDC, was determined by automatic Edman sequencing after reduction and alkylation. The sequence shows six Cys residues arranged in the pattern that defines the O-superfamily of conotoxins, and the sequence motif -gammaCCS-, which has only been found in the gamma-conotoxin family. The molecular mass of the native peptide was determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, which confirmed the chemical analyses and suggested a free C-terminus. The purified peptide elicited toxic effects in the freshwater snail Pomacea paludosa after intramuscular injection, but it had no effect when injected intracerebrally into mice. The structural similarity of peptide as7a to other gamma-conotoxins suggests that modulation of pacemaker channels could be responsible for its biological activity.
Zugasti-Cruz
Alejandro
A
Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, México D.F. 04510, Mexico.
Maillo
María
M
López-Vera
Estuardo
E
Falcón
Andrés
A
Heimer de la Cotera
Edgar P
EP
Olivera
Baldomero M
BM
Aguilar
Manuel B
MB
D000595:Amino Acid Sequence; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D020916:Conotoxins / Q000737:chemistry* / Q000494:pharmacology*; D052078:Conus Snail / Q000737:chemistry / Q000502:physiology; D005247:Feeding Behavior; D051379:Mice; D008969:Molecular Sequence Data; D008978:Mollusk Venoms / Q000737:chemistry; D011077:Polychaeta; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D020916:Conotoxins; D008978:Mollusk Venoms