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All total 22 Articles be found
All total 22 Articles be foundStalobacin: Discovery of Novel Lipopeptide Antibiotics with Potent Antibacterial Activity against Multidrug-Resistant Bacteria
Matsui, Kouhei,Matsui, Kouhei,Kan, Yukiko,Kikuchi, Junko,Matsushima, Keisuke,Takemura, Miki,Maki, Hideki,Kozono, Iori,Ueda, Taichi,Minagawa, Kazuyuki
supporting information, p. 6090 - 6095 (2020/07/10)
A novel lipopeptide antibiotic, stalobacin I (1), was discovered from a culture broth of an unidentified Gram-negative bacterium. Stalobacin I (1) had a unique chemical architecture composed of an upper and a lower half peptide sequence, which were linked via a hemiaminal methylene moiety. The sequence of 1 contained an unusual amino acid, carnosadine, 3,4-dihydroxyariginine, 3-hydroxyisoleucine, and 3-hydroxyaspartic acid, and a novel cyclopropyl fatty acid. The antibacterial activity of 1 against a broad range of drug-resistant Gram-positive bacteria was much stronger than those of "last resort"antibiotics such as vancomycin, linezolid, and telavancin (MIC 0.004-0.016 μg/mL). Furthermore, compound 1 induced a characteristic morphological change in Gram-positive and Gram-negative strains by inflating the bacterial cell body. The absolute configuration of a cyclopropyl amino acid, carnosadine, was determined by the synthetic study of its stereoisomers, which was an essential component for the strong activity of 1.
Rapid chemoenzymatic route to glutamate transporter inhibitor l-TFB-TBOA and related amino acids
Fu, Haigen,Younes, Sabry H. H.,Saifuddin, Mohammad,Tepper, Pieter G.,Zhang, Jielin,Keller, Erik,Heeres, André,Szymanski, Wiktor,Poelarends, Gerrit J.
supporting information, p. 2341 - 2344 (2017/03/20)
The complex amino acid (l-threo)-3-[3-[4-(trifluoromethyl)benzoylamino]benzyloxy]aspartate (l-TFB-TBOA) and its derivatives are privileged compounds for studying the roles of excitatory amino acid transporters (EAATs) in regulation of glutamatergic neurotransmission, animal behavior, and in the pathogenesis of neurological diseases. The wide-spread use of l-TFB-TBOA stems from its high potency of EAAT inhibition and the lack of off-target binding to glutamate receptors. However, one of the main challenges in the evaluation of l-TFB-TBOA and its derivatives is the laborious synthesis of these compounds in stereoisomerically pure form. Here, we report an efficient and step-economic chemoenzymatic route that gives access to enantio- and diastereopure l-TFB-TBOA and its derivatives at multigram scale.
Poecillastrin E, F, and G, cytotoxic chondropsin-type macrolides from a marine sponge Poecillastra sp.
Irie, Raku,Hitora, Yuki,Ise, Yuji,Okada, Shigeru,Takada, Kentaro,Matsunaga, Shigeki
, p. 1430 - 1434 (2018/02/13)
Poecillastrin E (1), F (2), and G (3) were isolated from a marine sponge Poecillastra sp. as the cytotoxic constituents. Their planar structures were determined by analyzing the MS and NMR spectra. They are closely related to the known poecillastrin C (4). The absolute configuration of the β-hydroxyaspartic acid (OHAsp) residue was determined to be D-threo by Marfey's analysis of the hydrolysate. The mode of lactone ring formation of OHAsp residue in 1–3 was determined by selective reduction of the ester linkage followed by acid hydrolysis.
Isolation and amino acid sequence of a dehydratase acting on D-erythro-3- hydroxyaspartate from Pseudomonas sp. N99, and its application in the production of optically active 3-hydroxyaspartate
Nagano, Hiroyuki,Shibano, Kana,Matsumoto, Yu,Yokota, Atsushi,Wada, Masaru
, p. 1156 - 1164 (2017/05/29)
An enzyme catalyzing the ammonia-lyase reaction for the conversion of D-erythro-3-hydroxyaspartate to oxaloacetate was purified from the cell-free extract of a soil-isolated bacterium Pseudomonas sp. N99. The enzyme exhibited ammonia-lyase activity toward L-threo-3-hydroxyaspartate and D-erythro-3- hydroxyaspartate, but not toward other 3-hydroxyaspartate isomers. The deduced amino acid sequence of the enzyme, which belongs to the serine/ threonine dehydratase family, shows similarity to the sequence of L-threo-3-hydroxyaspartate ammonia- lyase (EC 4.3.1.16) from Pseudomonas sp. T62 (74%) and Saccharomyces cerevisiae (64%) and serine racemase from Schizosaccharomyces pombe (65%). These results suggest that the enzyme is similar to L-threo-3-hydroxyaspartate ammonia-lyase from Pseudomonas sp. T62, which does not act on D-erythro-3-hydroxyaspartate. We also then used the recombinant enzyme expressed in Escherichia coli to produce optically pure L-erythro-3-hydroxyaspartate and D-threo-3-hydroxyaspartate from the corresponding DL-racemic mixtures. The enzymatic resolution reported here is one of the simplest and the first enzymatic method that can be used for obtaining optically pure L-erythro-3-hydroxyaspartate.
Ambiguity of NRPS Structure Predictions: Four Bidentate Chelating Groups in the Siderophore Pacifibactin
Hardy, Clifford D.,Butler, Alison
, p. 990 - 997 (2019/03/26)
Identified through a bioinformatics approach, a nonribosomal peptide synthetase gene cluster in Alcanivorax pacificus encodes the biosynthesis of the new siderophore pacifibactin. The structure of pacifibactin differs markedly from the bioinformatic prediction and contains four bidentate metal chelation sites, atypical for siderophores. Genome mining and structural characterization of pacifibactin is reported herein, as well as characterization of pacifibactin variants accessible due to a lack of adenylation domain fidelity during biosynthesis. A spectrophotometric titration of pacifibactin with Fe(III) and 13C NMR spectroscopy of the Ga(III)-pacifibactin complex establish 1:1 metal:pacifibactin coordination and reveal which of the bidentate binding groups are coordinated to the metal. The photoreaction of Fe(III)-pacifibactin, resulting from Fe(III) coordination of the β-hydroxyaspartic acid ligands, is reported.
