- First crystal structure of L-lysine 6-dehydrogenase as an NAD-dependent amine dehydrogenase
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A gene encoding an L-lysine dehydrogenase was identified in the hyperthermophilic archaeon Pyrococcus horikoshii. The gene was overexpressed in Escherichia coli, and its product was purified and characterized. The expressed enzyme is the most thermostable L-lysine dehydrogenase yet described, with a half-life of 180 min at 100 °C. The product of the enzyme's catalytic activity is Δ1-piperideine-6-carboxylate, which makes this enzyme an L-lysine 6-dehydrogenase (EC 1.4.1.18) that catalyzes the reductive deamination of the ∈-amino group and a type of NAD-dependent amine dehydrogenase. The three-dimensional structure of the enzyme was determined using the mercury-based multiple-wavelength anomalous dispersion method at a resolution of 2.44 A in the presence of NAD and sulfate ion. The asymmetric unit consisted of two subunits, and a crystallographic 2-fold axis generated the functional dimer. Each monomer consisted of a Rossmann fold domain and a C-terminal catalytic domain, and the fold of the catalytic domain showed similarity to that of saccharopine reductase. Notably, the structures of subunits A and B differed significantly. In subunit A, the active site contained a sulfate ion that was not seen in subunit B. Consequently, subunit A adopted a closed conformation, whereas subunit B adopted an open one. In each subunit, one NAD molecule was bound to the active site in an anti-conformation, indicating that the enzyme makes use of pro-R-specific hydride transfer between the two hydrides at C-4 of NADH (type A specificity). This is the first description of the three-dimensional structure of L-lysine 6-dehydrogenase as an NAD-dependent amine dehydrogenase.
- Yoneda, Kazunari,Fukuda, Junya,Sakuraba, Haruhiko,Ohshima, Toshihisa
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- Synthesis and application of novel s-guaiazulene sesquiterpenoid alkaloids
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The invention belongs to the field of synthetic pharmacochemistry and particularly relates to chemical synthesis and an application of a new framework of s-guaiazulene sesquiterpenoid alkaloids from Muriceides collaris. Muriceidine A is successfully designed and synthesized from s-guaiazulene and piperidine acid as raw materials with a chemical method. In order to verify the universality of the synthesis method, azulene aldehyde is linked with piperidine, methylpiperidine, pyrrole, piperidinemethanol, 4-hydroxypiperidine and other N-heterocycle fragments. Screening of antitumor activity in vitro finds that the IC50 values of structure optimized products 2 and 3 for 14 tumor cell strains including 231, MCF-7, K562, HCT-116, Hela, A549, H1975, HUVEC, MGC-803, SH-SY5Y, HO8910, Siha, PC-3 andBEL7402 are smaller than 10 mu M, and therefore, the new framework of s-guaiazulene sesquiterpenoid alkaloids can be used for research and development of antitumor drugs.
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- Preparation and application of guaifenazulene aldole dicondensate (by machine translation)
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The invention belongs to the field, and particularly relates to chemical preparation and application. When the problem group is subjected to chemical synthesis research on the skeleton by guaiguazulene and piperidine acid as raw materials, the derivative trans - 1, 2 - (1, 4 - diazulyl) ethene ene derivative of guaiabazulene is found. H1N1 Influenza virus testing, indicating that the compound is level, 25 mm in vitro antiviral activity superior to that of positive drug ribavirin. In vivo activity tests prove, the compound not only can inhibit the pneumonia symptoms, but also can reduce the titer, and the survival rate. , The survival rate, 5 mg/kg/day the lung virus titer . of virus-infected mice can be remarkably improved when stomach tube-like dosages are used for gastric lavage. In general, the activity of the compound is comparable, and the activity of the compound is comparable to that of oseltamivir. The utility model can be used for preparing antiviral drugs. The invention opens up a new way for deep research and development of new antiviral drugs, which is a new approach. (by machine translation)
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Paragraph 0008; 0021; 0024-0026
(2019/08/02)
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- Characterization of three novel enzymes with imine reductase activity
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Imine reductases (IRED) are promising catalysts for the synthesis of optically pure secondary cyclic amines. Three novel IREDs from Paenibacillus elgii B69, Streptomyces ipomoeae 91-03 and Pseudomonas putida KT2440 were identified by amino acid or structural similarity search, cloned and recombinantly expressed in E. coli and their substrate scope was investigated. Besides the acceptance of cyclic amines, also acyclic amines could be identified as substrates for all IREDs. For the IRED from P. putida, a crystal structure (PDB-code 3L6D) is available in the database, but the function of the protein was not investigated so far. This enzyme showed the highest apparent E-value of approximately Eapp = 52 for (R)-methylpyrrolidine of the IREDs investigated in this study. Thus, an excellent enantiomeric purity of >99% and 97% conversion was reached in a biocatalytic reaction using resting cells after 24 h. Interestingly, a histidine residue could be confirmed as a catalytic residue by mutagenesis, but the residue is placed one turn aside compared to the formally known position of the catalytic Asp187 of Streptomyces kanamyceticus IRED.
- Gand,Müller,Wardenga,H?hne
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p. 126 - 132
(2015/02/19)
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- The chemistry of escapin: Identification and quantification of the components in the complex mixture generated by an L-amino acid oxidase in the defensive secretion of the sea snail Aplysia Californica
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Escapin is an L-amino acid oxidase in the ink of a marine snail, the sea hare Aplysia californica, which oxidizes L-lysine (1) to produce a mixture of chemicals which is antipredatory and antimicrobial. The goal of our study was to determine the identity
- Kamio, Michiya,Ko, Ko-Chun,Zheng, Shilong,Wang, Binghe,Collins, Stacy L.,Gadda, Giovanni,Tai, Phang C.,Derby, Charles D.
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experimental part
p. 1597 - 1603
(2009/11/30)
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- Enzymatic synthesis of cyclic amino acids by N-methyl-l-amino acid dehydrogenase from Pseudomonas putida
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A new enzymatic system for the synthesis of enantiomerically pure cyclic amino acids (CAA) from the corresponding diamino acids or racemic CAA is described. α,ω-Diamino acids were oxidized to α-keto acids with amino acid oxidases (AAO). The α-keto acids were spontaneously transformed into cyclic imino acids in the reaction medium. The resulting imines were reduced to the l-form CAA with N-methyl-l-amino acid dehydrogenase (NMAADH) from Pseudomonas putida ATCC12633 using NADPH as a cofactor. l-Form CAA were also obtained from racemic CAA using d-amino-acid oxidase and NMAADH. Using this method, a new compound [1,4]-thiazepane-3-carboxylic acid (Fig. 1) was synthesized from aminopropylcystein.
- Yasuda, Mari,Ueda, Makoto,Muramatsu, Hisashi,Mihara, Hisaaki,Esaki, Nobuyoshi
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p. 1775 - 1779
(2007/10/03)
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