A single aspartate residue is involved in both intrinsic gating and blockage by Mg2+ of the inward rectifier, IRK1

P. R. Stanfield, N. W. Davies, P. A. Shelton, M. J. Sutcliffe, I. A. Khan, W. J. Brammar, E. C. Conley

    Research output: Contribution to journalArticlepeer-review

    Abstract

    1. We describe the effects on channel function of changing an aspartate residue (Asp172) in a membrane-spanning α-helix of the murine inward rectifier, IRK1, by site-directed mutagenesis. 2. Alteration of Asp172 to Glu (charged) or to Gln or Asn (polar but uncharged) produced functional channels showing inward rectification, though rectification was weaker with Gln and Asn. 3. Intrinsic gating around the potassium equilibrium potential, E(K), was conserved only if the charge on residue 172 was conserved. Currents through channels with Gln or Asn in this position showed no time dependence under hyperpolarization. 4. The change from Asp to Gln also reduced the affinity for internal Mg2+ at least fivefold, indicating that Asp172 also forms part of the site for Mg2+ blockage. 5. The consequences for channel structure of Asp172 lining the pore are discussed.
    Original languageEnglish
    Pages (from-to)1-6
    Number of pages5
    JournalJournal of Physiology
    Volume478
    Issue number1
    Publication statusPublished - 1994

    Fingerprint

    Dive into the research topics of 'A single aspartate residue is involved in both intrinsic gating and blockage by Mg2+ of the inward rectifier, IRK1'. Together they form a unique fingerprint.

    Cite this