Loss of cytosolic Mg²⁺ binding sites in the Thermotoga maritima CorA Mg²⁺ channel is not sufficient for channel opening.

ABSTRACT: The CorA Mg²⁺ channel is a homopentamer with five-fold symmetry. Each monomer consists of a large cytoplasmic domain and two transmembrane helices connected via a short periplasmic loop. In the Thermotoga maritima CorA crystal structure, a Mg²⁺ is bound between D89 of one monomer and D253 of the adjacent monomer (M1 binding site). Release of Mg²⁺ from these sites has been hypothesized to cause opening of the channel. We generated mutants to disrupt Mg²⁺ interaction with the M1 site. Crystal structures of the D89K/D253K and D89R/D253R mutants, determined to 3.05 and 3.3 Å, respectively, showed no significant structural differences with the wild type structure despite absence of Mg²⁺ at the M1 sites. Both mutants still appear to be in th

SUBMITTER: Kowatz T 

PROVIDER: S-EPMC6342003 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature