Structural locus of the pH gate in the Kir1.1 inward rectifier channel.

ABSTRACT: The closed-state crystal structure of prokaryotic inward rectifier, KirBac1.1, has implicated four inner helical phenylalanines near the cytoplasmic side as a possible locus of the channel gate. In the present study, we investigate whether this structural feature corresponds to the physiological pH gate of the renal inward rectifier, Kir1.1 (ROMK, KCNJ1). Kir1.1 is endogenous to the mammalian renal collecting duct and the thick ascending limb of Henle and is strongly gated by internal pH in the physiological range. It has four leucines (L160-Kir1.1b), homologous to the phenylalanines of KirBac1.1, which could function as steric gates near the convergence of the inner (M2) helices. Replacing these Leu-160 residues of Kir1.1b by smaller glycines abolished pH gating; however, replacement with

SUBMITTER: Sackin H 

PROVIDER: S-EPMC1305356 | biostudies-literature | 2005 Apr

REPOSITORIES: biostudies-literature