Mn2+ transport by Ca2+-ATPase of sarcoplasmic reticulum

Shinichirou Yonekura, Chikashi Toyoshima

Research output: Contribution to journalLetter

2 Citations (Scopus)

Abstract

Ca2+-ATPase of sarcoplasmic reticulum is known to pump Mn2+ in addition to Ca2+, but whether its transport mechanism is identical to that of Ca2+ is ambiguous. To clarify, we examined, by atomic absorption spectroscopy, competition between Mn2+ and Ca2+ in active transport using vesicles of sarcoplasmic reticulum (SR). Here, we demonstrate that Ca2+-ATPase transports Ca2+ and Mn2+ concomitantly but has a much lower affinity for Mn2+ (apparent Kd ~ 0.5 mm). Stoichiometries of transported ions per ATP hydrolysed, Vmax values and activation energies are very similar. Altogether, Ca2+-ATPase appears to use the same mechanism for transporting Mn2+ as that for Ca2+.

Original languageEnglish
Pages (from-to)2086-2095
Number of pages10
JournalFEBS Letters
DOIs
Publication statusPublished - Jul 1 2016

Keywords

  • Ca-ATPase
  • ion selectivity
  • ion transport

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology
  • Genetics
  • Molecular Biology
  • Structural Biology

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