Pore conformations and gating mechanism of a Cys-loop receptor.

ABSTRACT: Neurons regulate the propagation of chemoelectric signals throughout the nervous system by opening and closing ion channels, a process known as gating. Here, histidine-based metal-binding sites were engineered along the intrinsic pore of a chimeric Cys-loop receptor to probe state-dependent Zn(2+)-channel interactions. Patterns of Zn(2+) ion binding within the pore reveal that, in the closed state, the five pore-lining segments adopt an oblique orientation relative to the axis of ion conduction and constrict into a physical gate at their intracellular end. The interactions of Zn(2+) with the open state indicate that the five pore-lining segments should rigidly tilt to enable the movement of their intracellular ends away from the axis of ion conduction, so as to open the constriction (i.e.,

SUBMITTER: Paas Y 

PROVIDER: S-EPMC1276086 | biostudies-literature | 2005 Nov

REPOSITORIES: biostudies-literature