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. 1996 Jun 15;493(Pt 3):643–649. doi: 10.1113/jphysiol.1996.sp021411

The role of a single aspartate residue in ionic selectivity and block of a murine inward rectifier K+ channel Kir2.1.

C J Abrams 1, N W Davies 1, P A Shelton 1, P R Stanfield 1
PMCID: PMC1159014  PMID: 8799888

Abstract

1. The effects of Rb+ and Cs+ as blocking ions were investigated on wild-type and mutant forms of the inward rectifier K+ channel, IRK1 (Kir2.1). 2. In wild-type channels, Rb+ blockage was voltage dependent, increasing and then falling with increasing hyperpolarization. 3. Rb+ blockage was abolished by replacing Asp172 in the M2 domain of the pore-forming subunit by Asn, but was re-established by a change to Gln, narrowing the pore. Blocking affinity was reduced in D172Q, and was also reduced by replacing Gly168 in M2 by Ala. 4. Cs+ blockage was also abolished in D172N but was re-established in D172Q. 5. There appears to be a balance between charge and pore size in determining whether ions block or permeate. A major part of the selectivity of Kir2.1 is associated with Asp172 in the M2 domain.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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