| Project/Area Number |
21K15036
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 43030:Functional biochemistry-related
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| Research Institution | Tohoku University |
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Principal Investigator |
張 玉霞 東北大学, 多元物質科学研究所, 助教 (10899769)
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| Project Period (FY) |
2021-04-01 – 2022-03-31
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| Project Status |
Discontinued (Fiscal Year 2021)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2022: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2021: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | cryo-EM / SERCA2b / Calcium pump |
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| Outline of Research at the Start |
Sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) 2b pumps Ca2+ from the cytosol into the ER and maintains the cellular calcium homeostasis. We study on the structures and function of SERCA2b by high-end cryo-EM to comprehensively understand the mechanism of SERCA2b. We propose a new ATP entry pathway into its binding pocket based on our current new cryo-EM structure of SERCA2b in E12Ca2+ state. Besides, to gain deeper insight into SERCA2b under more physiological condition, we also plan to treat SERCA2b with ATP and explore the structural dynamics of SERCA2b by time-resolved cryo-EM analysis.
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| Outline of Annual Research Achievements |
We newly determined several cryo-EM structures of SERCA2b, including a high-energy E1P state with two bound Ca ions and the post-E1P state immediately after Ca release. The dataset in E2P state identified a new conformation that differs from the conventional E2P state and the subsequent E2-Pi state that can be regarded as a late-stage Ca-unbound intermediate. The cryo-EM structures suggested that SERCA2b adopts multiple conformations in reaction and generates preformed states closely resembling the next intermediate. These findings provide essential structural insight into how enzymes work; multiple sub-states, including one highly similar to a next intermediate, are formed in a reaction intermediate to facilitate the transition step and thereby drive the catalytic cycle efficiently.
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