Secondary structure of noxiustoxin and charybdotoxin from hydropathy power spectra.
The analysis of the hydropathy profile power spectra provides a basis for studies of pattern matching between the primary and secondary structure of peptides. The structural motif obtained with Noxiustoxin (NTX), the first K+ channel blocking peptide described, is composed of a N-terminal beta-strand, a central alpha-helix and a final beta-strand zone, probably forming a beta-sheet. These results were compared with those of Charybdotoxin (ChTX), a potent inhibitor of the high conductance Ca(2+)-activated K+ channel, which presents about 48% similarity with NTX in the amino acid sequence. Our prediction for ChTX secondary structure, which is known by 2D-NMR spectroscopy, yielded a Chou-Fasman quality index Q = 90%. The comparison between the two toxins has guided the interpretation of the data obtained.
Sacile
R
R
Dipartimento di Fisica Dell'Universita, Genova, Italy.
Ruggiero
C
C
Ballestrero
R
R
Possani
L D
LD
Prestipino
G
G
Rauch
G
G
D000595:Amino Acid Sequence; D018999:Charybdotoxin; D008969:Molecular Sequence Data; D026902:Potassium Channel Blockers; D017433:Protein Structure, Secondary; D012604:Scorpion Venoms / Q000737:chemistry*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012995:Solubility
D026902:Potassium Channel Blockers; D012604:Scorpion Venoms; D018999:Charybdotoxin; C052567:noxiustoxin