3CWN

Escherichia coli transaldolase b mutant f178y

3CWN の概要

• エントリーDOI: 10.2210/pdb3cwn/pdb
• 関連するPDBエントリー: 1ONR
• 分子名称: Transaldolase B, SULFATE ION (3 entities in total)
• 機能のキーワード: transaldolase, aldolase, directed evolution, cytoplasm, pentose shunt, transferase
• 由来する生物種: Escherichia coli (strain K12)
• 細胞内の位置: Cytoplasm (Probable): P0A870
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 75337.34

構造登録者

Sandalova, T.,Schneider, G.,Samland, A. (登録日: 2008-04-22, 公開日: 2008-08-05, 最終更新日: 2023-08-30)

主引用文献

Schneider, S.,Sandalova, T.,Schneider, G.,Sprenger, G.A.,Samland, A.K.
Replacement of a Phenylalanine by a Tyrosine in the Active Site Confers Fructose-6-phosphate Aldolase Activity to the Transaldolase of Escherichia coli and Human Origin.
J.Biol.Chem., 283:30064-30072, 2008

PubMed Abstract: Based on a structure-assisted sequence alignment we designed 11 focused libraries at residues in the active site of transaldolase B from Escherichia coli and screened them for their ability to synthesize fructose 6-phosphate from dihydroxyacetone and glyceraldehyde 3-phosphate using a newly developed color assay. We found one positive variant exhibiting a replacement of Phe(178) to Tyr. This mutant variant is able not only to transfer a dihydroxyacetone moiety from a ketose donor, fructose 6-phosphate, onto an aldehyde acceptor, erythrose 4-phosphate (14 units/mg), but to use it as a substrate directly in an aldolase reaction (7 units/mg). With a single amino acid replacement the fructose-6-phosphate aldolase activity was increased considerably (>70-fold compared with wild-type). Structural studies of the wild-type and mutant protein suggest that this is due to a different H-bond pattern in the active site leading to a destabilization of the Schiff base intermediate. Furthermore, we show that a homologous replacement has a similar effect in the human transaldolase Taldo1 (aldolase activity, 14 units/mg). We also demonstrate that both enzymes TalB and Taldo1 are recognized by the same polyclonal antibody.

PubMed: 18687684
DOI: 10.1074/jbc.M803184200

実験手法

X-RAY DIFFRACTION (1.4 Å)