Characterization of contryphans from Conus loroisii and Conus amadis that target calcium channels.
Peptides
; 27(11): 2647-54, 2006 Nov.
Article
em En
| MEDLINE
| ID: mdl-16945451
ABSTRACT
Distinctly different effects of two closely related contryphans have been demonstrated on voltage-activated Ca(2+) channels. The peptides Lo959 and Am975 were isolated from Conus loroisii, a vermivorous marine snail and Conus amadis, a molluscivore, respectively. The sequences of Lo959 and Am975 were deduced by mass spectrometric sequencing (MALDI-MS/MS) and confirmed by chemical synthesis. The sequences of Lo959, GCP(D)WDPWC-NH(2) and Am975, GCO(D)WDPWC-NH(2) (O 4-trans-hydroxyproline Hyp), differ only at residue 3; Pro in Lo959, Hyp in Am975, which is identical to contryphan-P, previously isolated from Conus purpurascens, a piscivore; while Lo959 is a novel peptide. Both Lo959 and Am975 undergo slow conformational interconversion under reverse-phase chromatographic conditions, a characteristic feature of all contryphans reported thus far. Electrophysiological studies performed using dorsal root ganglion neurons reveal that both peptides target high voltage-activated Ca(2+) channels. While Lo959 increases the Ca(2+) current, Am975 causes inhibition. The results establish that subtle sequence effects, which accompany post-translational modifications in Conus peptides, can have dramatic effects on target ion channels.
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Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Peptídeos Cíclicos
/
Canais de Cálcio
/
Conotoxinas
/
Caramujo Conus
Limite:
Animals
Idioma:
En
Revista:
Peptides
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Índia