- Asymmetric synthesis, biological activity and molecular docking studies of some unsaturated α-amino acids, derivatives of glycine, allylglycine and propargylglycine
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New enantiomerically enriched unsaturated tailor-made amino acids have been obtained. As a starting amino acid synthon for the asymmetric synthesis of tailor-made unsaturated amino acids, Ni(II) square-planar complexes of Schiff's bases of propargylglycine, allylglycine and glycine with chiral auxiliary (S)-2-N-(N’-benzylprolyl)-aminobenzophenone ((S)-BPB) were used. The Cα-alkylation of propargylglycine, allylglycine and glycine moieties resulted in the asymmetric synthesis of novel (S)-α-propargylglycine, (S)-α-allylglycine and glycine derivatives containing an aromatic group in the side chain (de 80–95,5%). After purification and cleavage of the metal complexes, the amino acids were isolated in high enantiomeric purity (ee >99%). Of the obtained seven tailor-made amino acids four showed inhibitory activity to collagenase G. The amino acid with an acetylene bond in the side chain (IC50 = 1.29 ± 0.02 mM) had the best result. Molecular docking showed that the amino acids with activity to collagenase G contained hydrogen and π-π bonds with the enzyme.
- Hayriyan, Liana A.,Karapetyan, Ani J.,Minasyan, Ella V.,Mkrtchyan, Anna F.,Paloyan, Ani M.,Panosyan, Henrik A.,Poghosyan, Artavazd S.,Saghyan, Ashot S.,Sahakyan, Lusine Yu.,Sargsyan, Armen S.,Tovmasyan, Anna S.,Tsaturyan, Avetis H.
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- Synthesis of D- and L-Phenylalanine Derivatives by Phenylalanine Ammonia Lyases: A Multienzymatic Cascade Process
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The synthesis of substituted D-phenylalanines in high yield and excellent optical purity, starting from inexpensive cinnamic acids, has been achieved with a novel one-pot approach by coupling phenylalanine ammonia lyase (PAL) amination with a chemoenzymatic deracemization (based on stereoselective oxidation and nonselective reduction). A simple high-throughput solid-phase screening method has also been developed to identify PALs with higher rates of formation of non-natural D-phenylalanines. The best variants were exploited in the chemoenzymatic cascade, thus increasing the yield and ee value of the D-configured product. Furthermore, the system was extended to the preparation of those L-phenylalanines which are obtained with a low ee value using PAL amination.
- Parmeggiani, Fabio,Lovelock, Sarah L.,Weise, Nicholas J.,Ahmed, Syed T.,Turner, Nicholas J.
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supporting information
p. 4608 - 4611
(2015/04/14)
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- Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway
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Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1cB elimination mechanism. All manner of things: A competing MIO-independent (MIO=4-methylideneimidazole-5-one) reaction pathway has been identified for phenylalanine ammonia lyases (PALs), which proceeds in a non-stereoselective manner, resulting in the generation of D-phenylalanine derivatives. The mechanism of D-amino acid formation is explored through isotopic-labeling studies and mutagenesis of key active-site residues.
- Lovelock, Sarah L.,Lloyd, Richard C.,Turner, Nicholas J.
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supporting information
p. 4652 - 4656
(2014/05/20)
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- BORON CONTAINING POLYBASIC BACTERIAL EFFLUX PUMP INHIBITORS AND THERAPEUTICS USES THEREOF
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Disclosed herein are polybasic bacterial efflux pump inhibitors containing boronic acid functionality and theft methods of synthesis, methods of use, and pharmaceutical compositions. Some embodiments include methods of treating or preventing a bacterial infection by co-administering to a subject infected with bacteria or at risk of infection with bacteria the efflux pump inhibitor with another anti-bacterial agent
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- Enantioselective synthesis of non-natural amino acids using phenylalanine dehydrogenases modified by site-directed mutagenesis
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The substrate scope of three mutants of phenylalanine dehydrogenase as biocatalysts for the transformation of a series of 2-oxo acids, structurally related to phenylpyruvic acid, to the analogous -amino acids, non-natural analogues of phenylalanine, has been investigated. The mutant enzymes are more tolerant than the wild type enzyme of the non-natural substrates, especially those with substituents at the 4-position on the phenyl ring. Excellent enantiocontrol resulted in all cases.
- Busca, Patricia,Paradisi, Francesca,Moynihan, Eamonn,Maguire, Anita R.,Engel, Paul C.
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p. 2684 - 2691
(2007/10/03)
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- Enzymatic peptide synthesis in frozen aqueous systems: Use of N(α)-unprotected unusual acyl donors
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α-Chymotrypsin (EC 3.4.21.1) was used for catalyzing the reaction of various N(α)-unprotected non-coded phenylalanine ester derivatives with H-Leu-NH2 and H-Arg-NH2 in frozen aqueous solution at -15°C. Compared with reactions at room temperature, a significant yield increasing effect could be established. The kinetic parameters of ester hydrolysis show that most of the unusual acyl donors (compared with the coded phenylalanine methyl ester) are well accepted substrates for α-chymotrypsin.
- Gerisch,Jakubke,Kreuzfeld
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p. 3039 - 3045
(2007/10/03)
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