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 Cd(2+) 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 Cd(2+). 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.
Wang
M H
MH
Department of Life Science, Pohang University of Science and Technology, Pohang, Kyun-Buk, 790-784, Korea. mhwang@postech.ac.kr
Oh
U
U
Rhee
H I
HI
D019943:Amino Acid Substitution / Q000235:genetics*; D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D004553:Electric Conductivity; D015640:Ion Channel Gating / Q000187:drug effects; D016297:Mutagenesis, Site-Directed / Q000235:genetics; D009865:Oocytes; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011487:Protein Conformation; D018075:RNA, Complementary / Q000235:genetics; D051637:Shaker Superfamily of Potassium Channels; D055672:Static Electricity; D014982:Xenopus laevis
D015221:Potassium Channels; D018075:RNA, Complementary; D051637:Shaker Superfamily of Potassium Channels; D002104:Cadmium; D011188:Potassium