Mechanism of protein lipoylation
| Project/Area Number |
11670126
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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 |
General medical chemistry
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| Research Institution | The University of Tokushima |
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Principal Investigator |
FUJIWARA Kazuko the University of Tokushima, the Institute for Enzyme Research, assistant professor, 分子酵素学研究センター, 助教授 (20108880)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | lipoate-activating enzyme / lipoic acid / lipoyltransferase / purification / glycine cleavage system / α-ketoacid dehydrogenase complex / cloning / acyl-CoA synthetase / 精製 / リポ酸-蛋白リガーゼ / 酵素精製 / 大量発現 |
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| Research Abstract |
Lipoic acid is a prosthetic group of H-protein of the glycine cleavage system and the acytransferase components of the pyruvate, α-ketoglutarate, and branched chain α-ketoacid dehydrogenase complexes. In mammals, lipoic acid is activated to lipoyl-nucleoside monophosphate by lipoate-activating enzyme (LAE) and then the lipoyl moiety is transferred to the proteins by the lipoyltransferase.
1. We purified LAE from bovine liver mitochondria to apparent homogeneity.
2. LAE activated lipoate with GTP at a 1000-fold higher rate than with ATP.The reaction absolutely required lipoate, GTP, and Mg^<2+> ion, and the reaction product was lipoyl-GMP.LAE activated both R- and S-lipoate to the respective lipoyl-GMP although preference for R-lipoate was observed. Lipoyltransferase equally transferred both R- and S-lipoyl moiety from respective activated lipoate to H-protein. However, only H-protein carrying R-lipoate was active in the glycine cleavage reaction.
3. We cloned cDNAs encoding a precursor LAE with a mitochondrial presequence. The nucleotide sequence has been submitted to the DDBJ/EMBLE/GenBank with accession number AB048289. Amino acid sequence of LAE is identical with that of xenobiotic/medium-chain fatty acid : CoA ligase III, but an amino acid substitution due to a single nucleotide polymorphism was found.
4. These results indicate that the medium-chain acyl-CoA synthetase in mitochondria has a novel function, the activation of lipoate with GTP.
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Report
(3 results)
Research Products
(13 results)
