- Cyclic Tetrapeptides with Synergistic Antifungal Activity from the Fungus Aspergillus westerdijkiae Using LC-MS/MS-Based Molecular Networking
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Fungal natural products play a prominent role in the development of pharmaceuticalagents. Two new cyclic tetrapeptides (CTPs), westertide A (1) and B (2), with eight known compounds (3-10) were isolated from the fungus Aspergillus westerdijkiae guided by
- Chen, Baosong,Dai, Huanqin,Han, Junjie,Li, Erwei,Liu, Hongwei,Lyu, Zhitang,Song, Fuhang,Sun, Jingzu,Wang, Hanying,Wang, Tao,Wang, Wenzhao,Zhang, Rui
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- A novel phenylalanine ammonia-lyase from Pseudozyma antarctica for stereoselective biotransformations of unnatural amino acids
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A novel phenylalanine ammonia-lyase of the psychrophilic yeast Pseudozyma antarctica (PzaPAL) was identified by screening microbial genomes against known PAL sequences. PzaPAL has a significantly different substrate binding pocket with an extended loop (26 aa long) connected to the aromatic ring binding region of the active site as compared to the known PALs from eukaryotes. The general properties of recombinant PzaPAL expressed in E. coli were characterized including kinetic features of this novel PAL with L-phenylalanine (S)-1a and further racemic substituted phenylalanines rac-1b-g,k. In most cases, PzaPAL revealed significantly higher turnover numbers than the PAL from Petroselinum crispum (PcPAL). Finally, the biocatalytic performance of PzaPAL and PcPAL was compared in the kinetic resolutions of racemic phenylalanine derivatives (rac-1a-s) by enzymatic ammonia elimination and also in the enantiotope selective ammonia addition reactions to cinnamic acid derivatives (2a-s). The enantiotope selectivity of PzaPAL with o-, m-, p-fluoro-, o-, p-chloro- and o-, m-bromo-substituted cinnamic acids proved to be higher than that of PcPAL.
- Varga, Andrea,Csuka, Pál,Sonesouphap, Orlavanah,Bánóczi, Gergely,To?a, Monica Ioana,Katona, Gabriel,Molnár, Zsófia,Bencze, László Csaba,Poppe, László,Paizs, Csaba
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p. 185 - 194
(2020/04/28)
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- Deracemization and stereoinversion to aromatic d-amino acid derivatives with ancestral l-amino acid oxidase
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Enantiomerically pure amino acid derivatives could be foundational compounds for peptide drugs. Deracemization of racemates to l-amino acid derivatives can be achieved through the reaction of evolved d-amino acid oxidase and chemical reductants, whereas deracemization to d-amino acid derivatives has not progressed due to the difficulty associated with the heterologous expression of l-amino acid oxidase (LAAO). In this study, we succeeded in developing an ancestral LAAO (AncLAAO) bearing broad substrate selectivity (13 l-amino acids) and high productivity through an Escherichia coli expression system (50.7 mg/L). AncLAAO can be applied to perform deracemization to d-amino acids in a similar way to deracemization to l-amino acids. In fact, full conversion (>99% ee, d-form) could be achieved for 16 racemates, including nine d,l-Phe derivatives, six d,l-Trp derivatives, and a d,l-phenylglycine. Taken together, we believe that AncLAAO could be a key enzyme to obtain optically pure d-amino acid derivatives in the future.
- Nakano, Shogo,Minamino, Yuki,Hasebe, Fumihito,Ito, Sohei
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p. 10152 - 10158
(2019/10/19)
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- Tailored Mutants of Phenylalanine Ammonia-Lyase from Petroselinum crispum for the Synthesis of Bulky l- and d-Arylalanines
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Tailored mutants of phenylalanine ammonia-lyase from Petroselinum crispum (PcPAL) were created and tested in ammonia elimination from various sterically demanding, non-natural analogues of phenylalanine and in ammonia addition reactions into the corresponding (E)-arylacrylates. The wild-type PcPAL was inert or exhibited quite poor conversions in both reactions with all members of the substrate panel. Appropriate single mutations of residue F137 and the highly conserved residue I460 resulted in PcPAL variants that were active in ammonia elimination but still had a poor activity in ammonia addition onto bulky substrates. However, combined mutations that involve I460 besides the well-studied F137 led to mutants that exhibited activity in ammonia addition as well. The synergistic multiple mutations resulted in substantial substrate scope extension of PcPAL and opened up new biocatalytic routes for the synthesis of both enantiomers of valuable phenylalanine analogues, such as (4-methoxyphenyl)-, (napthalen-2-yl)-, ([1,1′-biphenyl]-4-yl)-, (4′-fluoro-[1,1′-biphenyl]-4-yl)-, and (5-phenylthiophene-2-yl)alanines.
- Filip, Alina,Nagy, Emma Z. A.,Tork, Souad D.,Bánóczi, Gergely,To?a, Monica I.,Irimie, Florin D.,Poppe, László,Paizs, Csaba,Bencze, László C.
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p. 2627 - 2633
(2018/05/03)
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- Engineered Aminotransferase for the Production of d-Phenylalanine Derivatives Using Biocatalytic Cascades
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d-Phenylalanine derivatives are valuable chiral building blocks for a wide range of pharmaceuticals. Here, we developed stereoinversion and deracemization biocatalytic cascades to synthesize d-phenylalanine derivatives that contain electron-donating or -withdrawing substituents of various sizes and at different positions on the phenyl ring with a high enantiomeric excess (90 to >99 % ee) from commercially available racemic mixtures or l-amino acids. These whole-cell systems couple Proteus mirabilis l-amino acid deaminase with an engineered aminotransferase that displays native-like activity towards d-phenylalanine, which we generated from Bacillus sp. YM-1 d-amino acid aminotransferase. Our cascades are applicable to preparative-scale synthesis and do not require cofactor-regeneration systems or chemical reducing agents.
- Walton, Curtis J. W.,Parmeggiani, Fabio,Barber, Janet E. B.,McCann, Jenna L.,Turner, Nicholas J.,Chica, Roberto A.
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p. 470 - 474
(2017/12/15)
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- Bio-inspired enantioselective full transamination using readily available cyclodextrin
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The mimics of vitamin B6-dependent enzymes that catalyzed an enantioselective full transamination in the pure aqueous phase have been realized for the first time through the establishment of a new “pyridoxal 5′-phosphate (PLP) catalyzed non-covalent cyclodextrin (CD)-keto acid inclusion complexes” system, and various optically active amino acids have been obtained.
- Zhang, Shiqi,Li, Guangxun,Liu, Hongxin,Wang, Yingwei,Cao, Yuan,Zhao, Gang,Tang, Zhuo
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p. 4203 - 4208
(2017/02/05)
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- Single-Biocatalyst Synthesis of Enantiopure d-Arylalanines Exploiting an Engineered d-Amino Acid Dehydrogenase
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A practical and efficient biocatalytic synthesis of aromatic d-amino acids has been developed, based on the reductive amination of the corresponding α-keto acids via a recombinant whole cell system composed of an engineered dehydrogenase and cofactor recycling apparatus. The reaction was shown to give excellent enantioselectivity (≥98%) and good yields at the preparative scale across a broad range of substrates. Additionally, the structure of the variant enzyme was solved to allow rationalisation of the observed reaction rates. The engineered whole cell catalyst was also used to mediate the production of d-phenylalanine derivatives from racemic mixtures and cheaper l-amino acids by combining it with an enantiocomplementary deaminase. (Figure presented.).
- Parmeggiani, Fabio,Ahmed, Syed T.,Thompson, Matthew P.,Weise, Nicholas J.,Galman, James L.,Gahloth, Deepankar,Dunstan, Mark S.,Leys, David,Turner, Nicholas J.
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p. 3298 - 3306
(2016/10/20)
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- Novel chiral open-chain pyridoxamine catalyst and synthesis method and application thereof
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The invention relates to a novel chiral open-chain pyridoxamine catalyst and a synthesis method and application thereof. The structural general formula of the pyridoxamine catalyst is shown in the specification, wherein R1, R2, R3 and R4 are one of hydrogen, C1-24 alkyl, C1-24 alkyl containing substituent groups, substances shown in the specification and halogen, the substituent groups on C1-24 alkyl are a substance shown in the specification or a substance shown in the specification or a substance shown in the specification or O-Rw or S-Rw' or halogen, and Rx, Rx', Ry, Ry', Ry'', Rz, Rz', Rw and Rw' are one of hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, tertiary butyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl, benzyl, (1-phenyl)ethyl, 1-naphthyl, 2-naphthyl and halogen. Compared with the prior art, the pyridoxamine catalyst can achieve rapid and efficient synthesis of chiral amino acid, the preparation raw materials are easy to obtain, reaction conditions are mild, cost is low, and when the novel chiral open-chain pyridoxamine catalyst is used for a transamination reaction, the conditions are mild, and the reaction is stable.
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Paragraph 0175; 0176; 0177; 0178; 0197; 0198; 0199; 0200
(2017/01/19)
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- A new type of chiral-pyridoxamines for catalytic asymmetric transamination of α-keto acids
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A new type of chiral pyridoxamines bearing an adjacent chiral stereocenter has been developed via multi-step synthesis. The pyridoxamines displayed catalytic activity in asymmetric transamination of α-keto acids to give a variety of optically active amino acids in 27–78% yields with 34–62% ee's under very mild conditions. This work provides a synthetic strategy to construct new chiral pyridoxamines using bromopyridine 7 as a key synthon and also represents an early example of the applications of chiral pyridoxamines in asymmetric catalysis.
- Chen, Jianfeng,Zhao, Junyu,Gong, Xing,Xu, Dongfang,Zhao, Baoguo
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supporting information
p. 4612 - 4615
(2016/09/23)
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- Asymmetric synthesis of unnatural amino acids and tamsulosin chiral intermediate
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An efficient and enantioselective hydrogenation of N-acetylamino phenyl acrylic acids was successfully developed by using ruthenium catalyst. This methodology is important in the field of pharmaceuticals and provides a new process for the preparation of unnatural amino acids and tamsulosin chiral intermediate.
- Arava, Veera Reddy,Amasa, Srinivasulu Reddy,Goud Bhatthula, Bharat Kumar,Kompella, Laxmi Srinivas,Matta, Venkata Prasad,Subha
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supporting information
p. 2892 - 2897
(2013/09/02)
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- A simple and efficient diastereoselective Strecker synthesis of optically pure α-arylglycines
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A simple and economical method for the synthesis of highly functionalised α-amino nitriles, precursors to α-arylglycines with high optical purity is reported. For this purpose, (R) or (S)-2-amino-2- phenylethanol were used as chiral auxiliaries in a 1,3 Strecker reaction. Reactions were studied with a broad range of reagent systems for the generation of cyano nucleophile. Methodology has been extended for the synthesis of (S)-α-(2-iodo-5-nitrophenyl)glycine, (S)-α-(4- methoxyphenyl)glycine and (R)-β-(4-methoxyphenyl)alanine.
- Dave, Rajesh H.,Hosangadi, Bhaskar D.
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p. 11295 - 11308
(2007/10/03)
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- Asymmetric synthesis of α-amino acids by copper-catalyzed conjugate addition of Grignard reagents to optically active carbamatoacrylates
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Optically active ene carbamates were α-lithiated by lithium tetramethylpiperidide in the presence of trialkylstannyl chlorides to produce α-stannylated compounds. These underwent facile palladium-catalyzed couplings with acid chlorides to produce α-keto ene carbamates in good yield. Treatment of the α-stannyl ene carbamates with butyllithium followed by quenching with carbon dioxide and esterification gave optically active carbamatoacrylates. Copper-catalyzed addition of tert-butyl-, 1-naphthyl-, 2-propenyl-, p-methoxyphenyl-, (trimethylsilyl)methyl-, cyclohexyl-, 1-adamantyl-, and isopropyl Grignard reagents followed by quenching at -10 to 25°C and removal of the protecting groups gave the corresponding α-amino acids in 70-90% yield and 73-97% ee. Quenching the reaction at low temperature resulted in little if any asymmetric induction.
- Lander, Peter A.,Hegedus, Louis S.
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p. 8126 - 8132
(2007/10/02)
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- Total structures of cryptophycins, potent antitumor depsipeptides from the blue-green alga Nostoc sp. strain GSV 224
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Cryptophycin (A, 1), the major cytotoxin in the blue-green alga (cyanobacterium) Nostoc sp. GSV 224, shows excellent activity against solid tumors implanted in mice. This cyclic depsipeptide had previously been isolated from Nostoc sp. ATCC 53789 as an antifungal agent and its gross structure determined by researchers at Merck. The relative and absolute stereochemistry of this potentially important drug has now been established using a combination of chemical and spectral techniques. Six minor cryptophycins (B-G, 2-7) have also been isolated from GSV 224 and their total structures and cytotoxicities determined. Two types of cryptophycins are present in this alga, the major series possessing a monochlorinated L-O-methyltyrosine unit and the minor series possessing a nonchlorinated D-O-methyltyrosine unit. Structure-activity relationship (SAR) studies of the cryptophycins and several derivatives and degradation products (8-14) are described. Also presented are preliminary in vivo results for cryptophycin A against six solid tumors.
- Trimurtulu, Golakoti,Ohtani, Ikuko,Patterson, Gregory M. L.,Moore, Richard E.,Corbett, Thomas H.,Valeriote, Frederick A.,Demchik, Lisa
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p. 4729 - 4737
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF α-AMINO ACIDS BY ALKYLATION OF N--2,5-BIS(METHOXYMETHOXYMETHYL)PYRROLIDINE AND ENANTIOSELECTIVE SYNTHESIS OF PROTECTED (2S,9S)-2-AMINO-8-OXO-9,10-EPOXYDECANOIC ACID
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Highly diastereoselective alkylation (>=96percent de) of α-lithiated N--trans-2,5-bis(methoxymethoxymethyl)pyrrolidine and subsequent hydrolysis gave various α-amino acids of high optical purity.An unusual amino acid (2S,9S)-2-amino-8-oxo-9,10-epoxydecanoic acid was also synthesized enantioselectively in its N-protected form by using the alkylation of the above chiral glycine amide and asymmetric epoxidation as means of introducing C2 and C9 asymmetric centers, respectively.Aldol condensation reaction of the same lithiated glycine amide was also examined.
- Ikegami, Satoru,Uchiyama, Harumi,Hayama, Takashi,Katsuki, Tsutomu,Yamaguchi, Masaru
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p. 5333 - 5342
(2007/10/02)
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