TY - JOUR
T1 - Mn2+ transport by Ca2+-ATPase of sarcoplasmic reticulum
AU - Yonekura, Shin Ichiro
AU - Toyoshima, Chikashi
N1 - Funding Information:
This work was supported by a Specially Promoted Project grant from the Ministry of Education, Culture, Sports, Science and Technology of Japan (to C. T.). We thank David B McIntosh for improving the manuscript.
Publisher Copyright:
© 2016 Federation of European Biochemical Societies
PY - 2016/7/1
Y1 - 2016/7/1
N2 - 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+.
AB - 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+.
KW - Ca-ATPase
KW - ion selectivity
KW - ion transport
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U2 - 10.1002/1873-3468.12244
DO - 10.1002/1873-3468.12244
M3 - Article
C2 - 27279545
AN - SCOPUS:84979645695
SP - 2086
EP - 2095
JO - FEBS Letters
JF - FEBS Letters
SN - 0014-5793
ER -