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.
Secondary structure of noxiustoxin and charybdotoxin from hydropathy power spectra.
SACILE, ROBERTO;RUGGIERO, CARMELINA;
1994-01-01
Abstract
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.
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