- Biocontrolled formal inversion or retention of L -α-amino acids to enantiopure (R)- or (S)-hydroxyacids
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Natural L-α-amino acids and L-norleucine were transformed to the corresponding α-hydroxy acids by formal biocatalytic inversion or retention of absolute configuration. The one-pot transformation was achieved by a concurrent oxidation reduction cascade in aqueous media. A representative panel of enantiopure (R)- and (S)-2-hydroxy acids possessing aliphatic, aromatic and heteroaromatic moieties were isolated in high yield (67-85 %) and enantiopure form (>99 % ee) without requiring chromatographic purification.
- Busto, Eduardo,Grischek, Barbara,Kroutil, Wolfgang,Richter, Nina
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supporting information
p. 11225 - 11228,4
(2015/01/07)
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- Cloning and characterization of indolepyruvate decarboxylase from Methylobacterium extorquens AM1
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For the first time for methylotrophic bacteria an enzyme of phytohormone indole-3-acetic acid (IAA) biosynthesis, indole-3-pyruvate decarboxylase (EC 4.1.1.74), has been found. An open reading frame (ORF) was identified in the genome of facultative methylotroph Methylobacterium extorquens AM1 using BLAST. This ORF encodes thiamine diphosphate-dependent 2-keto acid decarboxylase and has similarity with indole-3-pyruvate decarboxylases, which are key enzymes of IAA biosynthesis. The ORF of the gene, named ipdC, was cloned into overexpression vector pET-22b(+). Recombinant enzyme IpdC was purified from Escherichia coli BL21(DE3) and characterized. The enzyme showed the highest k cat value for benzoylformate, albeit the indolepyruvate was decarboxylated with the highest catalytic efficiency (k cat/K m). The molecular mass of the holoenzyme determined using gel-permeation chromatography corresponds to a 245-kDa homotetramer. An ipdC-knockout mutant of M. extorquens grown in the presence of tryptophan had decreased IAA level (46% of wild type strain). Complementation of the mutation resulted in 6.3-fold increase of IAA concentration in the culture medium compared to that of the mutant strain. Thus involvement of IpdC in IAA biosynthesis in M. extorquens was shown.
- Fedorov,Doronina,Trotsenko
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experimental part
p. 1435 - 1443
(2011/12/15)
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