Squeezing at entrance of proton transport pathway in proton-translocating pyrophosphatase upon substrate binding

Yun Tzu Huang, Tseng Huang Liu, Shih Ming Lin, Yen Wei Chen, Yih Jiuan Pan, Ching Hung Lee, Yuh Ju Sun, Fan Gang Tseng, Rong Long Pan

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Homodimeric proton-translocating pyrophosphatase (H+- PPase; EC 3.6.1.1) is indispensable for many organisms in maintaining organellar pH homeostasis. This unique proton pump couples the hydrolysis of PPi to proton translocation across the membrane. H+-PPase consists of 14-16 relatively hydrophobic transmembrane domains presumably for proton translocation and hydrophilic loops primarily embedding a catalytic site. Several highly conserved polar residues located at or near the entrance of the transport pathway in H+-PPase are essential for proton pumping activity. In this investigation single molecule FRET was employed to dissect the action at the pathway entrance in homodimeric Clostridium tetani H+-PPase upon ligand binding. The presence of the substrate analog, imidodiphosphate mediated two sites at the pathway entrance moving toward each other. Moreover, single molecule FRET analyses after the mutation at the first proton-carrying residue (Arg-169) demonstrated that conformational changes at the entrance are conceivably essential for the initial step of H+-PPase proton translocation.Aworking model is accordingly proposed to illustrate the squeeze at the entrance of the transport pathway in H+-PPase upon substrate binding.

Original languageEnglish
Pages (from-to)19312-19320
Number of pages9
JournalJournal of Biological Chemistry
Volume288
Issue number27
DOIs
Publication statusPublished - 2013 Jul 5

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Huang, Y. T., Liu, T. H., Lin, S. M., Chen, Y. W., Pan, Y. J., Lee, C. H., Sun, Y. J., Tseng, F. G., & Pan, R. L. (2013). Squeezing at entrance of proton transport pathway in proton-translocating pyrophosphatase upon substrate binding. Journal of Biological Chemistry, 288(27), 19312-19320. https://doi.org/10.1074/jbc.M113.469353