1FNK

CRYSTAL STRUCTURE ANALYSIS OF CHORISMATE MUTASE MUTANT C88K/R90S

1FNK の概要

• エントリーDOI: 10.2210/pdb1fnk/pdb
• 関連するPDBエントリー: 1FNJ 2CHT
• 分子名称: PROTEIN (CHORISMATE MUTASE) (2 entities in total)
• 機能のキーワード: chorismate mutase, protein, mutant, pseudo-alpha beta-barrel, trimer, isomerase
• 由来する生物種: Bacillus subtilis
• 細胞内の位置: Cytoplasm : P19080
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14495.83

構造登録者

Kast, P.,Grisostomi, C.,Chen, I.A.,Li, S.,Krengel, U.,Xue, Y.,Hilvert, D. (登録日: 2000-08-22, 公開日: 2000-10-11, 最終更新日: 2024-10-30)

主引用文献

Kast, P.,Grisostomi, C.,Chen, I.A.,Li, S.,Krengel, U.,Xue, Y.,Hilvert, D.
A strategically positioned cation is crucial for efficient catalysis by chorismate mutase.
J.Biol.Chem., 275:36832-36838, 2000

PubMed Abstract: Combinatorial mutagenesis and in vivo selection experiments previously afforded functional variants of the AroH class Bacillus subtilis chorismate mutase lacking the otherwise highly conserved active site residue Arg(90). Here, we present a detailed kinetic and crystallographic study of several such variants. Removing the arginine side chain (R90G and R90A) reduced catalytic efficiency by more than 5 orders of magnitude. Reintroducing a positive charge to the active site through lysine substitutions restored more than a factor of a thousand in k(cat). Remarkably, the lysine could be placed at position 90 or at the more remote position 88 provided a sterically suitable residue was present at the partner site. Crystal structures of the double mutants C88S/R90K and C88K/R90S show that the lysine adopts an extended conformation that would place its epsilon-ammonium group within hydrogen-bonding distance of the ether oxygen of bound chorismate in the transition state. These results provide support for the hypothesis that developing negative charge in the highly polarized transition state is stabilized electrostatically by a strategically placed cation. The implications of this finding for the mechanism of all natural chorismate mutases and for the design of artificial catalysts are discussed.

PubMed: 10960481
DOI: 10.1074/jbc.M006351200

実験手法

X-RAY DIFFRACTION (2 Å)