3-methyl-2-oxobutanoate hydroxymethyltransferase from E. coli (KPHMT) and variants thereof. The 3,3,3-trisubstituted 2-oxoacids thus produced were converted into 2-oxolactones and 3-hydroxy acids and directly to ulosonic acid derivatives, all bearing gem-dialkyl, gem-cycloalkyl, and spirocyclic quaternary centers. In addition, some of these reactions use a single enantiomer from racemic nucleophiles to afford
Donor Promiscuity of a Thermostable Transketolase by Directed Evolution: Efficient Complementation of 1-Deoxy-<scp>d</scp>
-xylulose-5-phosphate Synthase Activity
Enzymes catalyzing asymmetric carboligation reactions typically show very high substrate specificity for their nucleophilic donor substrate components. Structure‐guided engineering of the thermostable transketolase from Geobacillus stearothermophilus by directed in vitro evolution yielded new enzyme variants that are able to utilize pyruvate and higher aliphatic homologues as nucleophilic components
Chemoselective detection and discrimination of carbonyl-containing compounds in metabolite mixtures by <sup>1</sup>
H-detected <sup>15</sup>
N nuclear magnetic resonance
作者:Andrew N. Lane、Sengodagounder Arumugam、Pawel K. Lorkiewicz、Richard M. Higashi、Sébastien Laulhé、Michael H. Nantz、Hunter N.B. Moseley、Teresa W.-M. Fan
DOI:10.1002/mrc.4199
日期:2015.5
NMR spectra of mixtures of metabolites extracted from cells or tissues are extremely complex, reflecting the large number of compounds that are present over a wide range of concentrations. Although multidimensional NMR can greatly improve resolution as well as improve reliability of compound assignments, lower abundance metabolites often remain hidden. We have developed a carbonyl‐selective aminooxy
limited synthetic applications of ω‐TA to access structurally diverse chiral amines and amino acids. Here we report the first example of an ω‐TA whose S pocket shows a non‐canonical steric constraint and readily accommodates up to an n‐butyl substituent. The relaxed substratespecificity of the (S)‐selective ω‐TA, cloned from Paracoccus denitrificans (PDTA), afforded efficient asymmetric syntheses of
Valine 375 and Phenylalanine 109 Confer Affinity and Specificity for Pyruvate as Donor Substrate in Acetohydroxy Acid Synthase Isozyme II from <i>Escherichia coli</i>
作者:Andrea Steinmetz、Maria Vyazmensky、Danilo Meyer、Ze′ev Barak、Ralph Golbik、David M. Chipman、Kai Tittmann
DOI:10.1021/bi100555q
日期:2010.6.29
result from a stronger hydrophobic interaction of the ethyl substituent of 2-KB with the sidechain of Trp464 in multiple, apparently committed steps of catalysis. Here, we have elucidated the molecular determinants conferring specificity for pyruvate as the sole physiological donor substrate. Structural studies and sequence alignments of the POX subfamily of ThDP enzymes that act on pyruvate indicate