期刊
BIOPHYSICAL JOURNAL
卷 84, 期 1, 页码 295-305出版社
BIOPHYSICAL SOCIETY
DOI: 10.1016/S0006-3495(03)74850-4
关键词
-
类别
资金
- NATIONAL INSTITUTE OF ARTHRITIS AND MUSCULOSKELETAL AND SKIN DISEASES [R01AR041691] Funding Source: NIH RePORTER
- NIAMS NIH HHS [AR41691, R01 AR041691] Funding Source: Medline
The cytoplasmic ends of the four S6 transmembrane segments of voltage-gated potassium channels converge in a bundle crossing that acts as the activation gate that opens in response to a depolarization. To explore whether the cytoplasmic extension of the S6 segment (the S6 tail) plays a role in coupling voltage sensor and activation gate movements, we examined the effect of cysteine substitution from residues N482 to T489 on the kinetics and voltage-dependence of S4 charge movement and on the kinetics of deactivation of ionic current. Among these mutants, F484C has the steepest voltage-dependent charge movement, the largest Q-Vshift, and the fastest OFF gating currents. Further study of the residue at position 484, using mutagenesis and modification of F484C by cysteine reagents, suggests that aromaticity at this position is essential to maintain normal coupling. We used periodicity analysis to appraise the possibility that the S6 tail has an a-helical structure. Although we obtained an alpha-periodicity index of 2.41 for gating current parameters, a new randomization test produced an indecisive conclusion about the secondary structure of this region. Taken together, our results suggest that the tail end of S6 plays an important role in coupling between activation gating and charge movement.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据