Phospholipid membrane-interaction of a peptide from S4 segment of KvAP K+ channel and the influence of the positive charges and an identified heptad repeat in its interaction with a S3 peptide

► In the present report we have investigated the structural and functional interaction between two small peptides derived from the S3 and S4 segments of KvAP K+ channel. ► We have identified and characterized a fairly conserved small heptad repeat sequence in S4 segment which was not reported before. ► Our results show that the identified short heptad repeat as well as the positive charges of S4 peptide contributes in its assembly and co-assembly with S3 peptide in the negatively charged lipid vesicles. ► The results suggested the presence of required amino acid sequence in both the selected short S3 and S4 segments of KvAP channel that enables these two peptides to interact with each other in membrane environments and could play a significant role in the oligomeric structure of the whole channel protein. ► The data raise the possibility of an important role of the heptad repeat sequence of S4 in the interaction of S3 and S4 segments in KvAP channel.