Open channel current noise analysis of S6 peptides from KvAP channel on bilayer lipid membrane shows bimodal power law scaling

• Power spectral density (PSD) of S6 single-channel open current traces has been analysed.
• Bimodal slope of PSD (1/f1/f and 1/f21/f2) in ion channels has been reported.
• Two modes of non-equilibrium ion transport in S6 channel best describe the bimodal Power law scaling.

Open channel current noise in synthetic peptide S6 of KvAP channel was investigated in a voltage clamp experiment on bilayer lipid membrane (BLM). It was observed that the power spectral density (PSD) of the component frequencies follows power law with different slopes in different frequency ranges. In order to know the origin of the slopes PSD analysis was done with signal filtering. It was found that the first slope in the noise profile follows 1/f1/f pattern which exists at lower frequencies and has high amplitude current noise, while the second slope corresponds to 1/f2−31/f2−3 pattern which exists at higher frequencies with low amplitude current noise. In addition, white noise was observed at very large frequencies. It was concluded that the plausible reason for the multiple power-law scaling is the existence of different modes of non-equilibrium ion transport through the S6 channel.