5vk6
Open conformation of KcsA non-inactivating E71A mutant
Structural highlights
FunctionKCSA_STRLI Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+).[1] Publication Abstract from PubMedC-type inactivation in potassium channels helps fine-tune long-term channel activity through conformational changes at the selectivity filter. Here, through the use of cross-linked constitutively open constructs, we determined the structures of KcsA's mutants that stabilize the selectivity filter in its conductive (E71A, at 2.25 A) and deep C-type inactivated (Y82A at 2.4 A) conformations. These structural snapshots represent KcsA's transient open-conductive (O/O) and the stable open deep C-type inactivated states (O/I), respectively. The present structures provide an unprecedented view of the selectivity filter backbone in its collapsed deep C-type inactivated conformation, highlighting the close interactions with structural waters and the local allosteric interactions that couple activation and inactivation gating. Together with the structures associated with the closed-inactivated state (C/I) and in the well-known closed conductive state (C/O), this work recapitulates, at atomic resolution, the key conformational changes of a potassium channel pore domain as it progresses along its gating cycle. The gating cycle of a K(+) channel at atomic resolution.,Cuello LG, Cortes DM, Perozo E Elife. 2017 Nov 22;6. doi: 10.7554/eLife.28032. PMID:29165243[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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