- Repurposing Nonheme Iron Hydroxylases to Enable Catalytic Nitrile Installation through an Azido Group Assistance
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Three mononuclear nonheme iron and 2-oxoglutarate dependent enzymes, l-Ile 4-hydroxylase, l-Leu 5-hydroxylase and polyoxin dihydroxylase, are previously reported to catalyze the hydroxylation of l-isoleucine, l-leucine, and l-α-amino-δ-carbamoylhydroxyvaleric acid (ACV). In this study, we showed that these enzymes can accommodate leucine isomers and catalyze regiospecific hydroxylation. On the basis of these results, as a proof-of-concept, we demonstrated that the outcome of the reaction can be redirected by installation of an assisting group within the substrate. Specifically, instead of canonical hydroxylation, these enzymes can catalyze non-native nitrile group installation when an azido group is introduced. The reaction is likely to proceed through C - H bond activation by an Fe(IV)-oxo species, followed by azido-directed C-N bond formation. These results offer a unique opportunity to investigate and expand the reaction repertoire of Fe/2OG enzymes.
- Davidson, Madison,McNamee, Meredith,Fan, Ruixi,Guo, Yisong,Chang, Wei-Chen
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supporting information
p. 3419 - 3423
(2019/03/07)
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- Synthesis of l-[4-11C]Asparagine by Ring-Opening Nucleophilic 11C-Cyanation Reaction of a Chiral Cyclic Sulfamidate Precursor
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The development of a convenient and rapid method to synthesize radiolabeled, enantiomerically pure amino acids (AAs) as potential positron emission tomography (PET) imaging agents for mapping various biochemical transformations in living organisms remains
- Xu, Youwen,Cankaya, Aylin Sibel,Hoque, Ruma,Lee, So Jeong,Shea, Colleen,Kersting, Lena,Schueller, Michael,Fowler, Joanna S.,Szalda, David,Alexoff, David,Riehl, Barbara,Gleede, Tassilo,Ferrieri, Richard A.,Qu, Wenchao
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p. 6848 - 6853
(2018/04/25)
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- Syntheses of optically pure α-amino acids from 3-amino-2-oxetanone salts
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A process for the preparation of optically pure α-amino acids comprising the nucleophilic ring-opening of 3-amino-2-oxetanone salts. N-Protected serine β-lactones are deprotected to form heretofore unknown 3-amino-2-oxetanone and its corresponding salts. In turn these previously unknown 3-amino-2-oxetanone salts may be used in the synthesis of other novel or rare stereochemically-pure free amino acids.
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- BIOSYNTHESIS OF β-(1,2,4-TRIAZOL-1-YL)ALANINE IN HIGHER PLANTS
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β-(1,2,4-triazol-1-yl)Alanine, an important metabolite of the triazole-based fungicide Myclobutanil, was shown to be derived from O-acetyl-L-serine and 1,2,4-triazole by cysteine synthase in higher plants.Some properties of this enzyme in the biosynthesis of β-(1,2,4-triazol-1-yl)alanine are described.
- Ikegami, Fumio,Komada, Yumiko,Kobori, Masuko,Hawkins, Douglas R.,Murakoshi, Isamu
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p. 2507 - 2508
(2007/10/02)
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- PURIFICATION AND PROPERTIES OF β-CYANO-L-ALANINE SYNTHASE FROM SPINACIA OLERACEA
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β-Cyano-L-alanine synthase was purified ca 6200-fold to homogeneity from the leaves of spinach (Spinacia oleracea).The purified enzyme has an apparent Mr of 60 000 and can be dissociated into identical subunits of Mr 30 000.The subunits each contain one molecule of pyridoxal 5'-phosphate.The Km value is 2.3 mM for L-cysteine and 0.73 mM for cyanide. β-Cyano-L-alanine synthase from S. oleracea also catalyses the formation of some S-substituted L-cysteines and some heterocyclic β-substituted alanines from L-cysteine or O-acetyl-L-serine.The specificity of these additional catalytic activities of the purified enzyme are compared with those of cysteine synthase purified from the same plant, and with those of β-cyano-L-alanine synthase purified from other sources.Some other properties, including the amino acid composition of the purified enzyme, are also described. - Key Word Index: Spinacia oleracea; Chenopodiaceae; spinach; β-cyano-L-alanine synthase; cysteine synthase; enzyme purification; amino acid composition; L-cysteine; O-acetyl-L-serine; β-cyano-L-alanine; heterocyclic β-substituted alanines.
- Ikegami, Fumio,Takayama, Kyoko,Tajima, Chiho,Murakoshi, Isamu
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p. 2011 - 2016
(2007/10/02)
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- ENZYMATIC SYNTHESIS OF THE NEUROEXCITATORY AMINO ACID QUISQUALIC ACID BY CYSTEINE SYNTHASE
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Key Word Index - Quisqualis indica var. villosa; Combretaceae; cysteine synthase; isoenzyme; enzyme purification; biosynthesis; heterocyclic β-substituted alanines; quisqualic acid; O-acetyl-L-serine; cysteine.Purification of cysteine synthase from the leaves of Quisqualis indica var. villosa reveals the presence of two forms of this enzyme, separated by chromatography on DEAE-Sephadex A-50.Isoenzyme A was purified 10 000-fold and had a specific activity of 10.8 U/mg protein.Isoenzyme B was purified 460-fold with a specific activity of 0.49 U/mg protein.Both isoenzymes have the same Mrs (58 000) and dissociate into identical subunits (Mr 29 000).The Km value of isoenzyme A is 1.9 mM for O-acetyl-L-serine and 59 μM for sulphide, while that of isoenzyme B is 7.1 mM for O-acetyl-L-serine and 4.0 mM for 3,5-dioxo-1,2,4-oxadiazolidine.Both isoenzymes catalyse the formation of cysteine from O-acetyl-L-serine and hydrogen sulphide, but only isoenzyme B catalyses the formation of L-quisqualic acid.Other significant differences occur in the substrate specificity of the two isoenzymes.Some properties of the purified cysteine synthase isoenzymes are also described.
- Murakoshi, Isamu,Kaneko, Masakazu,Koide, Chiharu,Ikegami, Fumio
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p. 2759 - 2764
(2007/10/02)
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- Formation of β-Cyanoalanine by Cyanide-resistant Strain Enterobacter sp. 10.1
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A cyanide-tolerant strain was isolated from a soil sample, and identified as belonging to the genus Enterobacter.The microorganism accumulated a compound which produced a green color with ninhydrin, in culture fluid containing sodium cyanide and sodium fumarate.This compound was isolated from the culture fluid in crystalline form by using ion axchange resin column chromatography, and was identified as β-cyano-L-alanine (β-CNAla).The compound accumulated in the culture fluid with the growth of the microorganism, and the amount of β-CNAla accumulated depended on the amount of sodium cyanide added.Both intact cells and a cell-free extract of the microorganism catalyzed the formation of β-CNAla from O-acetyl-L-serine with sodium cyanide as substrates.The β-CNAla-forming enzyme was found to be localized in both the cytoplasm and cytoplasmic membrane of this microorganism.
- Sakai, Takuo,Yanase, Hideshi,Sawada, Masahiko,Tonomura, Kenzo
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p. 2053 - 2062
(2007/10/02)
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