IONIC MOVEMENTS ACROSS NERVE CELL BODY MEMBRANES

长期目标是指定电压传感器和气孔 电压依赖性脑K+通道及其失活门 电压依赖的脑Na+通道。具体目标是：1) 建立用于单通道动力学的参考数据集 我们最近发现的大鼠脑K+通道drk1的电导 克隆、测序和表达；2)测试大范围变化的效果 在drk1和ENGINEER的非核心区使用重组方法 最小功能结构；3)将结构与功能通过 比较密切相关的单通道电流 同构变异；4)在区域中产生点突变或嵌合体 被认为是3C通道的电压传感器或导电孔或 Ne通道的失活门；5)突变大鼠的胞质连接蛋白 脑部Na+II检测其在失活门控中的作用。在所有情况下， 使用基于已知的模型来解释第三级通道结构 初级氨基酸序列。假说是通过注射来检验的 来自天然异构体的转录本和经过改造的突变体 非洲爪哇卵母细胞。从电压依赖关系的比较来看 在不同的状态之间转换为关闭状态和打开状态 蛋白质，可以推测其门控结构。从比较中得出 双离子溶液中的单通道电导，渗透率 可以推断出结构。结果及其解释将是 延伸到人脑K+和NC通道。关于结构的知识 负责电压门控和离子通量将提供合理的 癫痫、帕金森氏症和精神障碍的治疗基础 阿尔茨海默病。

The long-term objective is to specify the voltage sensor and the pore of voltage-dependent brain K+ channels and the inactivation gate of voltage-dependent brain Na+ channels. The specific aims are to: 1) establish a reference data set for the single channel kinetics and conductance of a rat brain K+ channel drk1, which we have recently cloned, sequenced and expressed; 2) test the effects of extensive changes in the non-core regions of drkl and engineer with recombinant methods a minimum functional structure; 3) correlate structure with function by comparing the single channels currents produced by closely related isomorphic variants; 4) produce point mutations or chimeras in regions thought to be the voltage sensor or conducting pore of 3C channels or the inactivation gate of Ne channels; 5) mutate the cytoplasmic linker in rat brain Na+II to test its role in inactivation gating. In all cases the tertiary channel structures are interpreted using models based upon known primary amino acid sequences. The hypotheses are tested by injecting transcripts from the natural isoforms and the engineered mutants into Xenopus oocytes. From a comparison of the voltage-dependence of transitions to and from the closed and open states among the different proteins, the gating structure may be inferred. From a comparison of single channel conductance in bi-ionic solutions, the permeation structure may be inferred. The results and their interpretation will be extended to human brain K+ and NC channels. Knowledge of the structures responsible for voltage gating and ionic flux will provide a rational basis for therapy of disorders such as epilepsy, Parkinsonism and Alzheimers disease.