3T8N

Crystal structure of ketosteroid isomerase Y16AD103A from Pseudomonas putida

3T8N の概要

• エントリーDOI: 10.2210/pdb3t8n/pdb
• 関連するPDBエントリー: 3M8C 3RGR 3T8U
• 分子名称: Steroid Delta-isomerase, SULFATE ION, {[-(BIS-CARBOXYMETHYL-AMINO)-ETHYL]-CARBOXYMETHYL-AMINO}-ACETIC ACID, ... (4 entities in total)
• 機能のキーワード: isomerase
• 由来する生物種: Pseudomonas putida (Arthrobacter siderocapsulatus)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 58422.13

構造登録者

Gonzalez, A.,Tsai, Y.,Schwans, J.,Sunden, F.,Herschlag, D. (登録日: 2011-08-01, 公開日: 2011-11-23, 最終更新日: 2024-10-16)

主引用文献

Schwans, J.P.,Sunden, F.,Gonzalez, A.,Tsai, Y.,Herschlag, D.
Evaluating the catalytic contribution from the oxyanion hole in ketosteroid isomerase.
J.Am.Chem.Soc., 133:20052-20055, 2011

PubMed Abstract: Prior site-directed mutagenesis studies in bacterial ketosteroid isomerase (KSI) reported that substitution of both oxyanion hole hydrogen bond donors gives a 10(5)- to 10(8)-fold rate reduction, suggesting that the oxyanion hole may provide the major contribution to KSI catalysis. But these seemingly conservative mutations replaced the oxyanion hole hydrogen bond donors with hydrophobic side chains that could lead to suboptimal solvation of the incipient oxyanion in the mutants, thereby potentially exaggerating the apparent energetic benefit of the hydrogen bonds relative to water-mediated hydrogen bonds in solution. We determined the functional and structural consequences of substituting the oxyanion hole hydrogen bond donors and several residues surrounding the oxyanion hole with smaller residues in an attempt to create a local site that would provide interactions more analogous to those in aqueous solution. These more drastic mutations created an active-site cavity estimated to be ~650 Å(3) and sufficient for occupancy by 15-17 water molecules and led to a rate decrease of only ~10(3)-fold for KSI from two different species, a much smaller effect than that observed from more traditional conservative mutations. The results underscore the strong context dependence of hydrogen bond energetics and suggest that the oxyanion hole provides an important, but moderate, catalytic contribution relative to the interactions in the corresponding solution reaction.

PubMed: 22053826
DOI: 10.1021/ja208050t

実験手法

X-RAY DIFFRACTION (1.47 Å)