134357-96-3Relevant articles and documents
Structural determination of stevastelins, novel depsipeptides from Penicillium sp.
Morino, Tomio,Shimada, Kei-Ichi,Masuda, Akira,Yamashita, Noriyuki,Nishimoto, Masakazu,Nishikiori, Takaaki,Saito, Seiichi
, p. 564 - 568 (1996)
Structures of novel immunosuppressants, stevastelin A, B and B31) were determined by their spectroscopic and chemical studies. Three stevastelins were shown to be cyclic depsipeptides composed of a fatty acid and three amino acid moieties. The sequence of these moieties was determined to be as 3,5-dihydroxy-2,4-dimethylstearylvalylthreonyl (or O-sulfonylthreonyl in stevastelin A)-O-acetylserine. Cyclic structures were shown to be formed by ester linkages between the carboxylic group of the O-acetylserine moiety and the 5-hydroxy group of the fatty acid moiety in stevastelin A and B, and the 3-hydroxy group of the fatty acid moiety in stevastelin B3.
New selectivity and turnover in peptide hydrolysis by metal complexes. A palladium(II) aqua complex catalyzes cleavage of peptides next to the histidine residue
Parac, Tatjana N.,Kosti?, Nenad M.
, p. 51 - 58 (1996)
This seems to be the first report that a transition-metal complex bonded to a histidine residue effects hydrolytic cleavage of a peptide next to this residue. Dipeptides AcHis-Aa in which the C-terminal amino acid designated Aa is Gly, Ala, Ser, Thr, Leu, Phe, and Tyr are completely hydrolyzed at 60 °C and 1.46 ≤ pD ≤ 2.61 in the presence of cis-[Pd(en)(H2O)2]-2+. The reaction is conveniently monitored by 1H NMR spectroscopy, and we report the kinetics. The reaction is unimolecular with respect to the palladium(II)-peptide complex. The cleavage is regioselective. In all the aforementioned dipeptides and in the tripeptide AcGly-His-Gly only the amide bond involving the carboxylic group of histidine is cleaved; the amide bond involving the amino group of histidine is not cleaved. When the carboxylic group of histidine is free, as in AcGly-His, cis-[Pd(en)(H2O)2]2+ does not effect hydrolysis. Lability of palladium(II) complexes and the acidic solution make possible a modest turnover in hydrolysis; the catalyst can cleave several equivalents of the dipeptide. The dipeptides AcHis-Aa, and also one product of their cleavage, AcHis, exist free and bound to the catalyst. They form similar palladium(II) complexes, five types of which are distinguishable by 1H NMR spectroscopy. The other products of cleavage, the amino acids Aa, exist free and in chelate complexes cis-[Pd(en)(N,O-Aa)]+. Partial binding of the catalyst to the peptide and to its cleavage products gives rise to an extended and complex equilibrium. Increase in pH favors catalytically-inactive palladium-(II)-peptide complexes, inhibits their conversion into catalytically-active complexes, and lowers the observed rate constant for hydrolysis. Because the equilibria are reversible, even the peptide bound in inactive complexes eventually becomes hydrolyzed. When palladium is removed as a diethyldithiocarbamate complex, the equilibria are abolished and only ethylenediamine, AcHis, and Aa remain. The rate constant for cleavage decreases as the steric bulk of the amino acid Aa increases and as intrapeptide hydrogen bonds mediated by water restrict the access of the palladium-(II) catalyst to the His-Aa bond. This hydrogen bonding is possible only when the amino acid Aa contains a hydroxyl group in a flexible side chain, as in Ser and Thr. The intrapeptide hydrogen bonding is impossible when a hydroxyl group is held relatively rigidly, as in Tyr, and, of course, when the hydroxyl group is absent, as in the other four amino acids. The kinetic effects of steric bulk and of specific hydrogen bonding may allow sequence selectivity in cleavage of peptides with palladium(II) complexes. This study points the way toward artificial metallopeptidases, coordination complexes with enzyme-like properties.
Cloning and characterization of D-threonine aldolase from the green alga Chlamydomonas reinhardtii
Hirato, Yuki,Tokuhisa, Mayumi,Tanigawa, Minoru,Ashida, Hiroyuki,Tanaka, Hiroyuki,Nishimura, Katsushi
, p. 18 - 23 (2017)
D-Threonine aldolase (DTA) catalyzes the pyridoxal 5’-phosphate (PLP)-dependent interconversion of D-threonine and glycine plus acetaldehyde. The enzyme is a powerful tool for the stereospecific synthesis of various β-hydroxy amino acids in synthetic organic chemistry. In this study, DTA from the green alga Chlamydomonas reinhardtii was discovered and characterized, representing the first report to describe the existence of eukaryotic DTA. DTA was overexpressed in recombinant Escherichia coli BL21 (DE3) cells; the specific activity of the enzyme in the cell-free extract was 0.8 U/mg. The recombinant enzyme was purified to homogeneity by ammonium sulfate fractionation, DEAE-Sepharose, and Mono Q column chromatographies (purified enzyme 7.0 U/mg). For the cleavage reaction, the optimal temperature and pH were 70?°C and pH 8.4, respectively. The enzyme demonstrated 90% of residual activity at 50?°C for 1?h. The enzyme catalyzed the synthesis of D- and D-allo threonine from a mixture of glycine and acetaldehyde (the diastereomer excess of D-threonine was 18%). DTA was activated by several divalent metal ions, including manganese, and was inhibited by PLP enzyme inhibitors and metalloenzyme inhibitors.
Site-specific labeling of synthetic peptide using the chemoselective reaction between N-methoxyamino acid and isothiocyanate
Hara, Toshiaki,Purwati, Euis Maras,Tainosyo, Akira,Kawakami, Toru,Hojo, Hironobu,Aimoto, Saburo
, p. 765 - 769 (2015)
Site-specific labeling of synthetic peptides carrying N-methoxyglycine (MeOGly) by isothiocyanate is demonstrated. A nonapeptide having MeOGly at its N-terminus was synthesized by the solid-phase method and reacted with phenylisothiocyanate under various conditions. In acidic solution, the reaction specifically gave a peptide having phenylthiourea structure at its N-terminus, leaving side chain amino group intact. The synthetic human β-defensin-2 carrying MeOGly at its N-terminus or the side chain amino group of Lys10 reacted with phenylisothiocyanate or fluorescein isothiocyanate also at the N-methoxyamino group under the same conditions, demonstrating that this method is generally useful for the site-specific labeling of linear synthetic peptides as well as disulfide-containing peptides.
Optical resolution by preferential crystallization and replacing crystallization of DL-allothreonine
Miyazaki,Morita,Shiraiwa,Kurokawa
, p. 1899 - 1903 (1994)
The ternary solubility diagranm, X-ray diffraction pattern, and infrared spectra have suggested that DL-allothreonine [DL-aThr] exists as a conglomerate. The optical resolution by successive preferential crystallization gave both D- and L-aThr of 95% optical purities in 9-13% degrees of resolution. The successive replacing crystallization was more successfully achieved by the coexisting 4-hydroxy-L-proline, as an optically active cosolute, in a racemic supersaturated solution. D-aThr of 94% optical purity was allowed to crystallize preferentially without seeding D-aThr in 24% degree of resolution, whereas L-aThr of 81% optical purity from the mother liquor was allowed to crystallize by seeding L-aThr in 22% degree of resolution. Recystallization of the obtained D- and L-aThr from water gave an optically pure form.
Foxo3a Inhibitors of Microbial Origin, JBIR-141 and JBIR-142
Kawahara, Teppei,Kagaya, Noritaka,Masuda, Yuichi,Doi, Takayuki,Izumikawa, Miho,Ohta, Kumiko,Hirao, Atsushi,Shin-Ya, Kazuo
, p. 5476 - 5479 (2015)
JBIR-141 (1) and JBIR-142 (2) were discovered as potent Foxo3a inhibitors that consist of three quite unique substructures, a 1-((dimethylamino)ethyl)-5-methyl-4,5-dihydrooxazole-4-carboxylic acid that is originated from Ala-Thr amino acid residues, a 3-acetoxy-4-amino-7-(hydroxy(nitroso)amino)-2,2-dimethylheptanoic acid, and an α-acyl tetramic acid fused with a 2-methylpropan-1-ol moiety. Their structures involving absolute configurations were determined by spectroscopic data, chemical degradation, anisotropy methods, and LC-MS analyses of diastereomeric derivatives. Compounds 1 and 2 exhibited specific inhibition against Foxo3a transcriptional activity with IC50 values of 23.1 and 166.2 nM, respectively.
Development of a high throughput screening tool for biotransformations utilising a thermophilic l-aminoacylase enzyme
Ngamsom,Hickey,Greenway,Littlechild,Watts,Wiles
, p. 81 - 86 (2010)
Micro-reactors containing a monolith-immobilised thermophilic l-aminoacylase, from Thermococcus litoralis, have been developed for use in biotransformation reactions and a study has been carried out to investigate the stereospecificity and stability of the immobilised enzyme. The potential to use the developed micro-reactors as a tool for rapid screening of enzyme specificity was demonstrated, confirming that the l-aminoacylase showed a similar substrate specificity to that previously reported of the free enzyme. From this baseline, the technique was employed as a tool to evaluate potential unreported substrates with N-benzoyl- (l-threonine, l-leucine and l-arginine) and N-acetyl- (d,l-serine, d,l-leucine, l-tyrosine and l-lysine) protecting groups. The order of preferred substrates was found to be Phe > Thr > Leu > Arg for N-benzoyl substrates and Phe ? Ser > Leu > Met > Tyr > Trp for N-acetyl substrates. It was found that by using the micro-reactor a significantly smaller quantity of enzyme and substrates was required. It was shown that the micro-reactors were still operational in the presence of selected organic solvents, such as ethanol, methanol, acetone, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results indicated that a combination of a small amount of an appropriate solvent (5% DMSO) and a higher reaction temperature could be employed in biotransformations where substrate solubility was an issue.
High fermentative production of L-threonine from acetate by a Brevibacterium flavum stabilized strain transformed with a recombinant plasmid carrying the Escherichia coli thr operon.
Ishida,Sato,Hashiguchi,Ito,Enei,Nakamori
, p. 1755 - 1756 (1993)
Decrease in L-threonine productivity caused not only by plasmid-free segregation but also by plasmid deletion was observed in a Brevibacterium flavum L-threonine producer when transformed with a recombinant plasmid carrying Escherichia coli thr operon. However, a recombinant strain, HT-16, was stabilized by the addition of trimethoprim (a selective marker on the vector) at concentration of 1000 micrograms/ml, which was rather higher than the minimum inhibitory one, into the stock culture medium. Strain HT-16 produced 64.4 g/liter of L-threonine, 30% higher than that of the host strain, after 92 h of cultivation in a small jar fermentor using acetic acid as a carbon source without trimethoprim.
Optimization of the kinetic resolution of the DL-phospho-monoesters of threonine and serine by random mutagenesis of the acid phosphatase from Salmonella enterica
Van Herk, Teunie,Hartog, Aloysius F.,Ruijssenaars, Harald J.,Kerkman, Richard,Schoemaker, Hans E.,Wever, Ron
, p. 1349 - 1352 (2007)
Acid phosphatases are enzymes with a broad substrate specificity showing hydrolytic activity towards several different organic phosphate monoesters, such as nucleotides and sugar phosphates. The acid phosphatase from Salmonella enterica ser. typhimurium LT2 (PhoN-Se) is able to hydrolyze O-phospho-DL-threonine to yield L-threonine with a very high enantioselectivity (E > 200). When O-phospho-DL-serine was hydrolyzed by PhoN-Se, D-serine was formed, however, the ee values rapidly dropped to 50 %. Random mutagenesis by error-prone PCR was performed on the phosphatase in order to increase its enantioselectivity in the formation of D-serine. Two variants with increased selectivity from a library of 9600 mutants have been found, N151D and V78L showing E values of 18.1 and 4.1, respectively, compared to 3.4 for the wild-type (WT) enzyme.
Asymmetric Synthesis of allo-Threonine and Threonine; the Use of a Chiral Pyridoxal-like Pyridinophane-Zinc Complex as an Enzyme Mimic
Kazuhara, Hiroyoshi,Watanabe, Naoyuki,Ando, Makoto
, p. 95 - 96 (1987)
allo-Threonine and threonine having 88 and 74percent enantiomeric excess (e.e.), respectively, were obtained in 1.7:1 ratio, by a biomimetic aldol condensation between acetaldehyde and the zinc chelate of a Schiff base produced from glycine and a chiral, pyridoxal-like pyridinophane derivative (2).
