Structural studies of ion permeation and Ca2+ blockage of a bacterial channel mimicking the cyclic nucleotide-gated channel pore.

ABSTRACT: Cyclic nucleotide-gated (CNG) channels play an essential role in the visual and olfactory sensory systems and are ubiquitous in eukaryotes. Details of their underlying ion selectivity properties are still not fully understood and are a matter of debate in the absence of high-resolution structures. To reveal the structural mechanism of ion selectivity in CNG channels, particularly their Ca(2+) blockage property, we engineered a set of mimics of CNG channel pores for both structural and functional analysis. The mimics faithfully represent the CNG channels they are modeled after, permeate Na(+) and K(+) equally well, and exhibit the same Ca(2+) blockage and permeation properties. Their high-resolution structures reveal a hitherto unseen selectivity filter architecture comprising three contigu

SUBMITTER: Derebe MG 

PROVIDER: S-EPMC3021057 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature