These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The external K+ concentration and mutations in the outer pore mouth affect the inhibition of kv1.5 current by Ni2+.
    Author: Kwan DC, Eduljee C, Lee L, Zhang S, Fedida D, Kehl SJ.
    Journal: Biophys J; 2004 Apr; 86(4):2238-50. PubMed ID: 15041663.
    Abstract:
    By examining the consequences both of changes of [K+]o and of point mutations in the outer pore mouth, our goal was to determine if the mechanism of the block of Kv1.5 ionic currents by external Ni2+ is similar to that for proton block. Ni2+ block is inhibited by increasing [K+]o, by mutating a histidine residue in the pore turret (H463Q) or by mutating a residue near the pore mouth (R487V) that is the homolog of Shaker T449. Aside from a slight rightward shift of the Q-V curve, Ni2+ had no effect on gating currents. We propose that, as with Ho+, Ni2+ binding to H463 facilitates an outer pore inactivation process that is antagonized by Ko+ and that requires R487. However, whereas Ho+ substantially accelerates inactivation of residual currents, Ni2+ is much less potent, indicating incomplete overlap of the profiles of these two metal ions. Analyses with Co2+ and Mn2+, together with previous results, indicate that for the first-row transition metals the rank order for the inhibition of Kv1.5 in 0 mM Ko+ is Zn2+ (KD approximately 0.07 mM) > or = Ni2+) (KD approximately 0.15 mM) > Co2+ (KD approximately 1.4 mM) > Mn2+ (KD > 10 mM).
    [Abstract] [Full Text] [Related] [New Search]