2006 Fiscal Year Final Research Report Summary
Study on ion-coupled subunit interaction of Na-HransbcatingV-ATPase
| Project/Area Number |
17570117
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | Ehime University |
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Principal Investigator |
KAKINUMA Yoshimi Ehime University, Faculty of Agriculture, Professor, 農学部, 教授 (80134394)
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| Project Period (FY) |
2005 – 2006
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| Keywords | V-ATPase / Sodium / Ion / Enterococcus hirae |
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| Research Abstract |
(i) The membrane rotor ring from the vacuolar-type (V-type) sodium ion-pumping adenosine triphosphatase (Na+-ATPase) from Enterococcus hirae consists of 10 NtpK subunits, which are homologs of the 16-kilodalton and 8-kilodalton proteolipids found in other V-ATPases and in FIFo-or F-ATPases, respectively. Each NtpK subunit has four transmembrane alpha helices, with a sodium ion bound between helices 2 and 4 at a site buried deeply in the membrane that includes the essential residue glutamate-139. This site is probably connected to the membrane surface by two half-channels in subunit NtpI, against which the ring rotates. Symmetry mismatch between the rotor and catalytic domains appears to be an intrinsic feature of both V-and F-ATPases.
(ii) By biochemical analysis of V-ATPase complex formation with the ntp gene-deleted mutant strains, we found that the VI portion is composed of subunit A, B, C, D, E, F, G and V0 portion of subunit I and K. Subunit B is not necessary to form the ACDIK complex, and subunit A plays a key role for V0V1 complex formation. All these results are important for understanding the molecular interaction of V-ATPase subunits during ion translocation.
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Research Products
(10 results)
