Structure of the subunit binding domain and dynamics of the di-domain region from the core of human branched chain α-ketoacid dehydrogenase complex

Chi Fon Chang, Hui Ting Chou, Yi Jan Lin, Shin Jye Lee, Jacinta L. Chuang, David T. Chuang, Tai Huang Huang

研究成果: 雜誌貢獻文章同行評審

12 引文 斯高帕斯(Scopus)

摘要

The homo-24-meric dihydrolipoyl transacylase (E2) scaffold of the human branched-chain α-ketoacid dehydrogenase complex (BCKDC) contains the lipoyl-bearing domain (hbLBD), the subunit-binding domain (hbSBD) and the inner core domain that are linked to carry out E2 functions in substrate channeling and recognition. In this study, we employed NMR techniques to determine the structure of hbSBD and dynamics of several truncated constructs from the E2 component of the human BCKDC, including hbLBD (residues 1-84), hbSBD (residues 111-149), and a di-domain (hbDD) (residues 1-166) comprising hbLBD, hbSBD and the interdomain linker. The solution structure of hbSBD consists of two nearly parallel helices separated by a long loop, similar to the structures of the SBD isolated from other species, but it lacks the short 310 helix. The NMR results show that the structures of hbLBD and hbSBD in isolated forms are not altered by the presence of the interdomain linker in hbDD. The linker region is not entirely exposed to solvent, where amide resonances associated with ∼50% of the residues are observable. However, the tethering of these two domains in hbDD significantly retards the overall rotational correlation times of hbLBD and hbSBD, changing from 5.54 ns and 5.73 ns in isolated forms to 8.37 ns and 8.85 ns in the linked hbDD, respectively. We conclude that the presence of the interdomain linker restricts the motional freedom of the hbSBD more significantly than hbLBD, and that the linker region likely exists as a soft rod rather than a flexible string in solution.

原文英語
頁(從 - 到)28345-28353
頁數9
期刊Journal of Biological Chemistry
281
發行號38
DOIs
出版狀態已發佈 - 2006 九月 22

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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