1NP3

Crystal structure of class I acetohydroxy acid isomeroreductase from Pseudomonas aeruginosa

1NP3 の概要

• エントリーDOI: 10.2210/pdb1np3/pdb
• 分子名称: Ketol-acid reductoisomerase (2 entities in total)
• 機能のキーワード: a deep figure-of-eight knot, c-terminal alpha-helical domain, oxidoreductase
• 由来する生物種: Pseudomonas aeruginosa
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 145866.14

構造登録者

Ahn, H.J.,Eom, S.J.,Yoon, H.-J.,Lee, B.I.,Cho, H.,Suh, S.W. (登録日: 2003-01-17, 公開日: 2003-05-06, 最終更新日: 2024-03-13)

主引用文献

Ahn, H.J.,Eom, S.J.,Yoon, H.-J.,Lee, B.I.,Cho, H.,Suh, S.W.
Crystal Structure of Class I Acetohydroxy Acid Isomeroreductase from Pseudomonas aeruginosa
J.Mol.Biol., 328:505-515, 2003

PubMed Abstract: Acetohydroxy acid isomeroreductase (AHIR) is a key enzyme in the biosynthesis of branched-chain amino acids. We have determined the first crystal structure of a class I AHIR from Pseudomonas aeruginosa at 2.0 A resolution. Its dodecameric architecture of 23 point group symmetry is assembled of six dimeric units and dimerization is essential for the formation of the active site. The dimeric unit of P.aeruginosa AHIR partially superimposes with a three-domain monomer of spinach AHIR, a class II enzyme. This demonstrates that the so-called plant-specific insert in the middle of spinach AHIR is structurally and functionally equivalent to the C-terminal alpha-helical domain of P.aeruginosa AHIR, and the C-terminal alpha-helical domain was duplicated during evolution from the shorter, class I AHIRs to the longer, class II AHIRs. The dimeric unit of P.aeruginosa AHIR possesses a deep figure-of-eight knot, essentially identical with that in the spinach AHIR monomer. Thus, our work lowers the likelihood of the previous proposal that "domain duplication followed by exchange of a secondary structure element can be a source of such a knot in the protein structure" being correct.

PubMed: 12691757
DOI: 10.1016/S0022-2836(03)00264-X

実験手法

X-RAY DIFFRACTION (2 Å)