Improving and Inverting C<sub>β</sub>-Stereoselectivity of Threonine Aldolase via Substrate-Binding-Guided Mutagenesis and a Stepwise Visual Screening
作者:Qijia Chen、Xi Chen、Jinhui Feng、Qiaqing Wu、Dunming Zhu、Yanhe Ma
DOI:10.1021/acscatal.9b00859
日期:2019.5.3
Threoninealdolase (TA)-catalyzed aldol condensation is a powerful tool for C–C bond formation under mild conditions, but the low Cβ-stereoselectivity has hampered its wide application. A stepwise visual screening method was developed to measure the activity and stereoselectivity of threonine aldolase-catalyzed aldol condensation by employing a stereoselective phenylserine dehydratase, enabling direct
Characteristics of <scp>l</scp>-threonine transaldolase for asymmetric synthesis of β-hydroxy-α-amino acids
作者:Lian Xu、Li-Chao Wang、Xin-Qi Xu、Juan Lin
DOI:10.1039/c9cy01608b
日期:——
L-threo-β-hydroxy-α-amino acid so far reported by enzymatic synthesis. Finally, synthesis of L-threo-p-methylsulfonylphenylserine at a 100 mL scale by whole-cell biocatalysis was conducted. This is the first systematic report of L-threonine transaldolase as a robust biocatalyst for preparation of β-hydroxy-α-amino acids, which can provide new insights for β-hydroxy-α-amino acidssynthesis.
Threonine aldolases—an emerging tool for organic synthesis
作者:Johannes Steinreiber、Kateryna Fesko、Christoph Reisinger、Martin Schürmann、Friso van Assema、Michael Wolberg、Daniel Mink、Herfried Griengl
DOI:10.1016/j.tet.2006.11.035
日期:2007.1
In a systematic study, 21 ring-substituted benzaldehydes were reacted with glycine under catalysis with a L-threonine aldolase (LTA) from Pseudomonas putida and a D-threonine aldolase (DTA) from Alcaligenes xylosoxidans to form the corresponding beta-hydroxy-alpha-amino acids 1-18. DTA proved to be highly selective with ee's > 99% (D) and de's up to 99% (syn). Two thiamphenicol precursors were synthesized utilizing DTA on a preparative scale. LTA-catalyzed reactions led to ee's > 99% (L) but low to moderate de's (20-50%, syn). (c) 2006 Elsevier Ltd. All rights reserved.
A study towards efficient l-threonine aldolase-catalyzed enantio- and diastereoselective aldol reactions of glycine with substituted benzaldehydes: biocatalyst production and process development
The development of aldol reactions of glycine with substituted benzaldehydes in the presence of recombinant L-threonine aldolases from Escherichia coli or Saccharomyces cerevisiae, which were obtained with excellent overexpression data, has been carried out. When using glycine and ortho-chlorobenzaldehyde, a high conversion of >95%, an enantioselectivity of >99% ee, and a diastereoselectivity with d.r.(syn/anti) = 80:20 was obtained for the resulting beta-hydroxy alpha-amino acid in such a biotransformation. It should be noted that this enzymatic process can be conducted at an elevated substrate concentration of 250 mM. (C) 2011 Elsevier Ltd. All rights reserved.
Mutability‐Landscape‐Guided Engineering of
<scp>l</scp>
‐Threonine Aldolase Revealing the Prelog Rule in Mediating Diastereoselectivity of C−C Bond Formation
The Prelogrule in l-threonine aldolase holds that when the Cα anion of PLP-Gly attacks the carbonyl carbon atom of the aldehyde from the re-face, the (2S,3S)-configured product is formed, whereas attack from the si-face forms the (2S,3R)-configured product. Guided by this rule, mutants of LTA with improved diastereoselectivity of 99.2 %syn and 97.4 %anti were obtained.
L-苏氨酸醛缩酶的Prelog规则认为,当PLP-Gly的Cα阴离子从re-face攻击醛的羰基碳原子时,形成(2S ,3S)-构型产物,而攻击来自si面形成 (2 S ,3 R )-配置的产品。在此规则的指导下,获得了具有 99.2%顺式和 97.4%反的改进的非对映选择性的 LTA 突变体。