Work

Charybdotoxin and noxiustoxin, two homologous peptide inhibitors of the K+(Ca2+) channel

Year: 1988

Type: article

Abstract: We show that noxiustoxin (NTX), like charybdotoxin (CTX) described by others, affects Ca2+-activated K+ channels of skeletal muscle (K+(Ca2+) channels). Chemical characterization of CTX shows that it is similar to NTX. Although the amino-terminal amino acid of CTX is not readily available, the molecule was partially sequenced after CNBr cleavage. A decapeptide corresponding to the C-terminal region of NTX shows 60% homology to that of CTX, maintaining the cysteine residues at the same positions. While CTX blocks the K+ (Ca2+) channels with a Kd of 1-3 nM, for NTX it is approx. 450 nM. Both peptides can interact simultaneously with the same channel. NTX and CTX promise to be good tools for channel isolation.

Source: FEBS Letters

DOI: 10.1016/0014-5793(88)81439-x

Authors: Hector H. Valdivia, Jeffrey S. Smith, Brian M. Martin, Roberto Coronado, Lourival D. Possani

Institutions: Baylor College of Medicine, National Institutes of Health, National Institute of Mental Health, Universidad Nacional Autónoma de México

Language: English

Topic: Ion channel regulation and function

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: bronze