The functional role of arginine 901 at the C-terminus of the human anion transporter band 3 protein

Shinya Takazaki, Yoshito Abe, Donchon Kang, Chunyan Li, Xiuri Jin, Tadashi Ueda, Naotaka Hamasaki

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Abstract

To determine which arginine residues are responsible for band 3-mediated anion transport, we analyzed hydroxyphenylglyoxal (HPG)-modified band 3 protein in native erythrocyte membranes. HPG-modification leads to inhibition of the transport of phosphoenolpyruvate, a substrate for band 3-mediated transport. We analyzed the HPG-modified membranes by reverse phase-HPLC, and determined that arginine 901 was modified by HPG. To determine the role of Arg 901 in the conformational change induced by anion exchange, we analyzed HPG-modification of the membranes when 4,4′-dinitrostilbene-2,2′-disulfonic acid (DNDS) or diethypyrocarbonate (DEPC) was present. DNDS and DEPC fix band 3 in the outward and inward conformations, respectively. HPG-modification was unaffected in the presence of DEPC but decreased in the presence of DNDS. In addition to that, 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS), which specifically reacts with the outward conformation of band 3, did not react with HPG-modified membranes. Furthermore, we expressed a band 3 mutant in which Arg 901 was replaced by alanine (R901A) on yeast membranes. The kinetic parameters indicated that the R901A mutation affected the rate of conformational change of the band 3 protein. From these results, we conclude that the most C-terminal arginine, Arg 901, has a functional role in the conformational change that is necessary for anion transport.

Original languageEnglish
Pages (from-to)903-912
Number of pages10
JournalJournal of biochemistry
Volume139
Issue number5
DOIs
Publication statusPublished - May 1 2006

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All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology

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