Mutation of His 834 in human anion exchanger 1 affects substrate binding

Shinya Takazaki, Yoshito Abe, Tomohiro Yamaguchi, Mikako Yagi, Tadashi Ueda, Dongchon Kang, Naotaka Hamasaki

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Anion exchanger 1 (AE1 or band 3) is responsible for Cl--HCO3- exchange on erythrocyte membrane. Previously, we showed that band 3 is fixed in an inward-facing conformation by specific modification of His 834 with DEPC, resulting in a strong inhibition of its anion transport activity. To clarify the physiological role of His 834, we evaluated the sulfate transport activities of various band 3 mutants: different mutants at His 834 and alanine mutants of peripheral residues around 834 (Lys 829-Phe 836) in yeast cell membranes. The Km values of the His 834 mutants were 4-10 times higher than that of the wild type, while their Vmax values were barely lower than that of wild type. Meanwhile, the Km values of the peripheral alanine mutants were only slightly increased. These data suggest that His 834 is critically important for the efficient binding of sulfate anion, but not for the conformational change induced by substrate binding.

Original languageEnglish
Pages (from-to)903-908
Number of pages6
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1798
Issue number5
DOIs
Publication statusPublished - May 2010

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Cell Biology

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