5n78
From Proteopedia
Crystal structure of the cytosolic domain of the CorA Mg2+ channel from Escherichia coli in complex with magnesium and cobalt hexammine
Structural highlights
FunctionCORA_ECOLI Mediates influx of magnesium ions. Can also mediate cobalt and manganese uptake (PubMed:780341). Alternates between open and closed states. Activated by low cytoplasmic Mg(2+) levels. Inactive when cytoplasmic Mg(2+) levels are high (By similarity).[UniProtKB:Q9WZ31][1] Publication Abstract from PubMedStructures of the Mg2+ bound (closed) and apo (open) states of CorA suggests that channel gating is accomplished by rigid-body motions between symmetric and asymmetric assemblies of the cytosolic portions of the five subunits in response to ligand (Mg2+) binding/unbinding at interfacial sites. Here, we structurally and biochemically characterize the isolated cytosolic domain from Escherichia coli CorA. The data reveal an Mg2+-ligand binding site located in a novel position between each of the five subunits and two Mg2+ ions trapped inside the pore. Soaking experiments show that cobalt hexammine outcompetes Mg2+ at the pore site closest to the membrane. This represents the first structural information of how an analog of hexa-hydrated Mg2+ (and competitive inhibitor of CorA) associates to the CorA pore. Biochemical data on the isolated cytoplasmic domain and full-length protein suggests that gating of the CorA channel is governed cooperatively. Structure and Cooperativity of the Cytosolic Domain of the CorA Mg2+ Channel from Escherichia coli.,Lerche M, Sandhu H, Flockner L, Hogbom M, Rapp M Structure. 2017 Aug 1;25(8):1175-1186.e4. doi: 10.1016/j.str.2017.05.024. Epub, 2017 Jun 29. PMID:28669631[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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