화학공학소재연구정보센터
Biochemical and Biophysical Research Communications, Vol.275, No.3, 720-724, 2000
Amino acid substitution within the S2 and S4 transmembrane segments in Shaker potassium channel modulates channel gating
To investigate of the gating properties in the voltage-activated potassium channel, we have mutated a variety of S2 and S4 residues in the Shaker potassium protein. Results showed that the R365C and R368C, but not the E283C, R362C, R365S, R368S or the ShB-IR, were sensitive to micromolar concentrations of Cd2+ ions, This indicates that R365 and R368 play a crucial role in the channel gating due to a conformational modulation of the channel structure, Doubly mutated channels of the E283C/R365E and E283C/R368E caused a transient increase in current amplitude, which reached a peak within a few seconds and then decreased toward initial levels, despite the continual presence of Cd2+. Taken together, our results suggest that E283, R365, and R368 form a network of strong, local, and electrostatic interactions that relate closely to the mechanism of the channel gating,