Versatile architecture of a bacterial aconitase B and its catalytic performance in the sequential reaction coupled with isocitrate dehydrogenase

Daisuke Tsuchiya, Nobutaka Shimizu, Masaru Tomita

研究成果: Article査読

5 被引用数 (Scopus)

抄録

Aconitase B (AcnB) and isocitrate dehydrogenase (ICDH) catalyze the sequential reaction in the Krebs cycle. Since each enzyme was characterized as an independent protein in a diluted condition, the catalytic performance within the cellular metabolism remains unclear. In particular, high macromolecular concentration in the cytosol promotes weak interactions, which affects structure and function of the proteins. We found that the two bacterial enzymes exhibit variable catalytic performance of the sequential reaction, depending on the oligomerization state. The small-angle solution X-ray scattering and the chemical crosslinking analyses revealed that not only the two enzymes but also the fusion protein of the two enzymes assume homodimers in solution. Interestingly, the fusion protein maintains the homodimeric architecture of ICDH, but not AcnB. Instead, one of the two monomeric AcnB regions associates with the homodimeric ICDH region. The fusion protein displayed different catalytic performance of the sequential reaction from that observed in the mixture of the AcnB and ICDH proteins in an equimolar ratio. Connecting the two proteins by a flexible linker yielded a locally high concentration to promote the weak protein-protein interaction. The versatile architecture of AcnB may alter the metabolic process involving the Krebs cycle.

本文言語English
ページ(範囲)1847-1856
ページ数10
ジャーナルBiochimica et Biophysica Acta - Proteins and Proteomics
1784
11
DOI
出版ステータスPublished - 2008 11月 1

ASJC Scopus subject areas

  • 分析化学
  • 生物理学
  • 生化学
  • 分子生物学

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