The invention belongs to the technical field of biological medicines, and relates to a mutants of mu-
conotoxin KIIIA rich in positive charges and application of the mutants. The
mutant is obtained by implementing site-specific
mutagenesis at the following positions on a
mutant as shown in SEQ ID NO.1 in a sequence table: S6R; the
amino acid sequence of the
mutant is as shown in SEQ ID NO. 2 in a sequence table. According to the invention, systematic structural optimization is carried out on a parent
peptide KIIIA containing three pairs of disulfide bonds, and a strategy of combining
disulfide bond deletion and
amino acid site-
directed mutagenesis is adopted, so that a mutant which is simple and convenient to synthesize and has a remarkable inhibition effect on a NaV1.4 channel is obtained. The mutant has
high activity, high stability and better pharmacokinetic characteristics, and has wide development potential.