RESUMEN
A novel inhibitor of voltage-gated K(+) channels has been purified to homogeneity from the venom of the black scorpion Orthochirus scrobiculosus. This toxin, named OsK2, has been characterized as a 28-residue peptide, containing six conserved cysteine residues and was shown to be a potent and selective blocker of Kv1.2 channels (K(d) = 97 nM). OsK2 is the second member of the 13th subfamily of short-chain K(+) channel-blocking peptides known thus far and is therefore called alpha-KTx 13.2.
Asunto(s)
Bloqueadores de los Canales de Potasio , Canales de Potasio con Entrada de Voltaje , Canales de Potasio , Venenos de Escorpión/química , Venenos de Escorpión/farmacología , Secuencia de Aminoácidos , Animales , Cromatografía , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Cisteína/química , ADN Complementario/metabolismo , Dípteros , Relación Dosis-Respuesta a Droga , Electrofisiología , Saltamontes , Cinética , Canal de Potasio Kv.1.2 , Espectrometría de Masas , Datos de Secuencia Molecular , Músculos/efectos de los fármacos , Neuronas/efectos de los fármacos , Oocitos/metabolismo , Péptidos/química , Plásmidos/metabolismo , Venenos de Escorpión/aislamiento & purificación , Escorpiones , Análisis de Secuencia de Proteína , Homología de Secuencia de Aminoácido , Factores de TiempoRESUMEN
alpha-Latrotoxin (alpha-LTX) binding sites to functionally active monoclonal antibodies (MA) A4 and A24 were localized using three approaches: hydrolysis of the toxin followed by the N-terminal sequencing of immunoreactive peptides; the study of antibody interaction with several recombinant alpha-LTX fragments; and Western immunoblotting of synthetic overlapping peptides (6-8 aa) whose structures correspond to that of the immunoreactive alpha-LTX fragment. It was shown that the MA A4 epitope is located within the F234-M294 protein fragment and that of MA A24 interacts with the fragment 347FDKDIT352.
