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Structure, function, and ion-binding properties of a K+ channel stabilized in the 2,4-ion–bound configuration.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America . 8/20/2019, Vol. 116 Issue 34, p16829-16834. 6p. - Publication Year :
- 2019
-
Abstract
- Here, we present the atomic resolution crystallographic structure, the function, and the ion-binding properties of the KcsA mutants, G77A and G77C, that stabilize the 2,4-ion–bound configuration (i.e., water, K+, water, K+-ion–bound configuration) of the K+ channel’s selectivity filter. A full functional and thermodynamic characterization of the G77A mutant revealed wild-type–like ion selectivity and apparent K+-binding affinity, in addition to showing a lack of C-type inactivation gating and a marked reduction in its single-channel conductance. These structures validate, from a structural point of view, the notion that 2 isoenergetic ion-bound configurations coexist within a K+ channel’s selectivity filter, which fully agrees with the water–K+-ion–coupled transport detected by streaming potential measurements. [ABSTRACT FROM AUTHOR]
- Subjects :
- *STREAM measurements
*POTASSIUM channels
Subjects
Details
- Language :
- English
- ISSN :
- 00278424
- Volume :
- 116
- Issue :
- 34
- Database :
- Academic Search Index
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 138259692
- Full Text :
- https://doi.org/10.1073/pnas.1901888116