| Item type |
学術雑誌論文 / Journal Article_02(1) |
| 公開日 |
2012-05-17 |
| タイトル |
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タイトル |
Ca^<2+> Release to Lumen from ADP-sensitive Phosphoenzyme E1PCa_2 without Bound K^+ of Sarcoplasmic Reticulum Ca^<2+>-ATPase |
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言語 |
en |
| 言語 |
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言語 |
eng |
| 資源タイプ |
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資源タイプ |
journal article |
| 著者 |
山崎, 和生
Daiho, Takashi
Danko, Stefania
Suzuki, Hiroshi
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| 書誌情報 |
Journal of Biological Chemistry
巻 285,
号 49,
p. 38674-38683,
発行日 2010-12-01
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| ISSN |
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収録物識別子タイプ |
PISSN |
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収録物識別子 |
0021-9258 |
| DOI |
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識別子タイプ |
DOI |
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関連識別子 |
10.1074/jbc.M110.183343 |
| 抄録 |
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内容記述タイプ |
Abstract |
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内容記述 |
During Ca^<2+> transport by sarcoplasmic reticulum Ca^<2+>-ATPase, the conformation change of ADP-sensitive phosphoenzyme (E1PCa_2) to ADP-insensitive phosphoenzyme (E2PCa_2) is followed by rapid Ca^<2+> release into the lumen. Here, we find that in the absence of K^+, Ca^<2+> release occurs considerably faster than E1PCa_2 to E2PCa_2 conformation change. Therefore, the lumenal Ca^<2+> release pathway is open to some extent in the K^+-free E1PCa_2 structure. The Ca^<2+> affinity of this E1P is as high as that of the unphosphorylated ATPase (E1), indicating the Ca^<2+> binding sites are not disrupted. Thus, bound K^+ stabilizes the E1PCa_2 structure with occluded Ca^<2+>, keeping the Ca^<2+> pathway to the lumen closed. We found previously (Yamasaki, K., Wang, G., Daiho, T., Danko, S., and Suzuki, H. (2008) J. Biol. Chem. 283, 29144-29155) that the K^+ bound in E2P reduces the Ca^<2+> affinity essential for achieving the high physiological Ca^<2+> gradient and to fully open the lumenal Ca^<2+> gate for rapid Ca^<2+> release (E2PCa_2 → E2P + 2Ca^<2+>). These findings show that bound K^+ is critical for stabilizing both E1PCa_2 and E2P structures, thereby contributing to the structural changes that efficiently couple phosphoenzyme processing and Ca^<2+> handling. |
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言語 |
en |
| 注記 |
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内容記述タイプ |
Other |
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注記 |
© 2010 by The American Society for Biochemistry and Molecular Biology, Inc. |
| 資源タイプ |
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内容記述タイプ |
Other |
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資源タイプ |
text |
| 著者版フラグ |
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出版タイプ |
VoR |
| フォーマット |
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内容記述タイプ |
Other |
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内容記述 |
application/pdf |
| ID(XooNIps) |
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20937807 |
| 閲覧数(XooNIps) |
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| ダウンロード数(XooNIps) |
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828 |
4496.pdf (4.4 MB)
