Kappa-conotoxin RIIIJ is a conopeptide to inhibit voltage-gated potassium channels, however, its detailed folding structures have yet to be studied. With the advance in computing power, it is possible to use the HP model to analyze all its possible folding structures. In this study,
the amino acid sequences of kappa-conotoxin RIIIJ and its four mutageneses were converted into ten HP sequences according to the normalized hydrophobicity index. All 282 429 536 481 possible folding structures in each HP sequence were found using the 2-dimensional HP model, and the detailed
folding structures at native state were studied. The results showed that kappa-conotoxin RIIIJ had 180 and 90 folding structures at their native state with minimal energy of –9 and –10 at pH 2 and pH 7; its mutagenesis (6-8) TPP -> SLN increased the numbers of the folding structures
to 456 and 564 at pH 2 and pH 7; whereas its mutageneses (6-11) TPPKKH -> SLNLRL, (9- 11) KKH -> LRL, and (10-11) KH -> RL decreased the numbers of the folding structures to 60, 30 and 90 at both pH levels, respectively. Thereafter, the normalized hydrophobicity index was employed
to distinguish those native states, and attempts were made to explain the effect of mutageneses on potassium channels in terms of the number of folding structures and numerical native states.
Protein & Peptide Letters publishes short papers in all important aspects of protein and peptide research, including structural studies, recombinant expression, function, synthesis, enzymology, immunology, molecular modeling, drug design etc. Manuscripts must have a significant element of novelty, timeliness and urgency that merit rapid publication. Reports of crystallisation, and preliminary structure determinations of biologically important proteins are acceptable. Purely theoretical papers are also acceptable provided they provide new insight into the principles of protein/peptide structure and function.