25191-17-7Relevant academic research and scientific papers
Protein thiocarboxylate-dependent methionine biosynthesis in Wolinella succinogenes
Krishnamoorthy, Kalyanaraman,Begley, Tadhg P.
, p. 379 - 386 (2011)
Thiocarboxylated proteins are important intermediates in a variety of biochemical sulfide transfer reactions. Here we identify a protein thiocarboxylate-dependent methionine biosynthetic pathway in Wolinella succinogenes. In this pathway, the carboxy terminal alanine of a novel sulfur transfer protein, HcyS-Ala, is removed in a reaction catalyzed by a metalloprotease, HcyD. HcyF, an ATP-utilizing enzyme, catalyzes the adenylation of HcyS. HcyS acyl-adenylate then undergoes nucleophilic substitution by bisulfide produced by Sir to give the HcyS thiocarboxylate. This adds to O-acetylhomoserine to give HcyS-homocysteine in a PLP-dependent reaction catalyzed by MetY. HcyD-mediated hydrolysis liberates homocysteine. A final methylation completes the biosynthesis. The biosynthetic gene cluster also encodes the enzymes involved in the conversion of sulfate to sulfide suggesting that sulfate is the sulfur source for protein thiocarboxylate formation in this system.
Squamins C–F, four cyclopeptides from the seeds of Annona globiflora
Sosa-Rueda, Javier,Domínguez-Meléndez, Vanihamin,Ortiz-Celiseo, Araceli,López-Fentanes, Fernando C.,Cuadrado, Cristina,Fernández, José J.,Daranas, Antonio Hernández,Cen-Pacheco, Francisco
, (2021/08/04)
Four cyclic octapeptides, squamins C–F, were isolated from the seeds of Annona globiflora Schltdl. These compounds share part of their amino acid sequence, -Pro-Met(O)-Tyr-Gly-Thr-, with previously reported squamins A and B. Their structures were determined using NMR spectroscopic techniques together with quantum mechanical calculations (QM-NMR), ESI-HRMS data and a modified version of Marfey's chromatographic method. All compounds showed cytotoxic activity against DU-145 (human prostate cancer) and HeLa (human cervical carcinoma) cell lines. Clearly, A. globiflora is an important source of bioactive molecules, which could promote the sustainable exploitation of this undervalued specie.
Recreating the natural evolutionary trend in key microdomains provides an effective strategy for engineering of a thermomicrobial N-demethylase
Gu, Zhenghua,Guo, Zitao,Shao, Jun,Shen, Chen,Shi, Yi,Tang, Mengwei,Xin, Yu,Zhang, Liang
, (2022/03/09)
N-demethylases have been reported to remove the methyl groups on primary or secondary amines, which could further affect the properties and functions of biomacromolecules or chemical compounds; however, the substrate scope and the robustness of N-demethylases have not been systematically investigated. Here we report the recreation of natural evolution in key microdomains of the Thermomicrobium roseum sarcosine oxidase (TrSOX), an N-demethylase with marked stability (melting temperature over 100 C) and enantioselectivity, for enhanced substrate scope and catalytic efficiency on -C-N-bonds. We obtained the structure of TrSOX by crystallization and X-ray diffraction (XRD) for the initial framework. The natural evolution in the nonconserved residues of key microdomains—including the catalytic loop, coenzyme pocket, substrate pocket, and entrance site—was then identified using ancestral sequence reconstruction (ASR), and the substitutions that accrued during natural evolution were recreated by site-directed mutagenesis. The single and double substitution variants catalyzed the N-demethylation of N-methyl-L-amino acids up to 1800- and 6000-fold faster than the wild type, respectively. Additionally, these single substitution variants catalyzed the terminal N-demethylation of non-amino-acid compounds and the oxidation of the main chain -C-N- bond to a -C=N- bond in the nitrogen-containing heterocycle. Notably, these variants retained the enantioselectivity and stability of the initial framework. We conclude that the variants of TrSOX are of great potential use in N-methyl enantiomer resolution, main-chain Schiff base synthesis, and alkaloid modification or degradation.
A Photoregulated Racemase Mimic
Saha, Monochura,Hossain, Munshi Sahid,Bandyopadhyay, Subhajit
supporting information, p. 5220 - 5224 (2021/01/18)
The racemase enzymes convert L-amino acids to their D-isomer. The reaction proceeds through a stepwise deprotonation–reprotonation mechanism that is assisted by a pyridoxal phosphate (PLP) coenzyme. This work reports a PLP–photoswitch–imidazole triad where the racemization reaction can be controlled by light by tweaking the distance between the basic residue and the reaction centre.
Rational engineering ofAcinetobacter tandoiiglutamate dehydrogenase for asymmetric synthesis ofl-homoalanine through biocatalytic cascades
Diao, Shiqing,Jiang, Shuiqin,Liu, Yan,Sun, Yangyang,Wang, Hualei,Wang, Liuzhu,Wei, Dongzhi
, p. 4208 - 4215 (2021/06/30)
l-Homoalanine, a useful building block for the synthesis of several chiral drugs, is generally synthesized through biocascades using natural amino acids as cheap starting reactants. However, the addition of expensive external cofactors and the low efficiency of leucine dehydrogenases towards the intermediate 2-ketobutyric acid are two major challenges in industrial applications. Herein, a dual cofactor-dependent glutamate dehydrogenase fromAcinetobacter tandoii(AtGluDH) was identified to help make full use of the intracellular pool of cofactors when using whole-cell catalysis. Through reconstruction of the hydrophobic network between the enzyme and the terminal methyl group of the substrate 2-ketobutyric acid, the strict substrate specificity ofAtGluDH towards α-ketoglutarate was successfully changed, and the activity obtained by the most effective mutant (K76L/T180C) was 17.2 times higher than that of the wild-type protein. A three-enzyme co-expression system was successfully constructed in order to help release the mass transfer restriction. Using 1 Ml-threonine, which is close to the solubility limit, we obtained a 99.9% yield ofl-homoalanine in only 3.5 h without adding external coenzymes to the cascade, giving 99.9% ee and a 29.2 g L?1h?1space-time yield. Additionally, the activities of the engineeredAtGluDH towards some other hydrophobic amino acids were also improved to 1.1-11.2 fold. Therefore, the engineering design of some dual cofactor-dependent GluDHs could not only eliminate the low catalytic activity of unnatural substrates but also enhance the cofactor utilization efficiency of these enzymes in industrial applications.
Biosynthesis ofl-alanine fromcis-butenedioic anhydride catalyzed by a triple-enzyme cascadeviaa genetically modified strain
Cui, Ruizhi,Liu, Zhongmei,Yu, Puyi,Zhou, Li,Zhou, Zhemin
supporting information, p. 7290 - 7298 (2021/09/28)
In industry,l-alanine is biosynthesized using fermentation methods or catalyzed froml-aspartic acid by aspartate β-decarboxylase (ASD). In this study, a triple-enzyme system was developed to biosynthesizel-alanine fromcis-butenedioic anhydride, which was cost-efficient and could overcome the shortcomings of fermentation. Maleic acid formed bycis-butenedioic anhydride dissolving in water was transformed tol-alanineviafumaric acid andl-asparagic acid catalyzed by maleate isomerase (MaiA), aspartase (AspA) and ASD, respectively. The enzymatic properties of ASD from different origins were investigated and compared, as ASD was the key enzyme of the triple-enzyme cascade. Based on cofactor dependence and cooperation with the other two enzymes, a suitable ASD was chosen. Two of the three enzymes, MaiA and ASD, were recombinant enzymes cloned into a dual-promoter plasmid for overexpression; another enzyme, AspA, was the genomic enzyme of the host cell, in which AspA was enhanced by a T7promoter. Two fumarases in the host cell genome were deleted to improve the utilization of the intermediate fumaric acid. The conversion of whole-cell catalysis achieved 94.9% in 6 h, and the productivity given in our system was 28.2 g (L h)?1, which was higher than the productivity that had been reported. A catalysis-extraction circulation process for the synthesis ofl-alanine was established based on high-density fermentation, and the wastewater generated by this process was less than 34% of that by the fermentation process. Our results not only established a new green manufacturing process forl-alanine production fromcis-butenedioic anhydride but also provided a promising strategy that could consider both catalytic ability and cell growth burden for multi-enzyme cascade catalysis.
Highly Stable Zr(IV)-Based Metal-Organic Frameworks for Chiral Separation in Reversed-Phase Liquid Chromatography
Jiang, Hong,Yang, Kuiwei,Zhao, Xiangxiang,Zhang, Wenqiang,Liu, Yan,Jiang, Jianwen,Cui, Yong
supporting information, p. 390 - 398 (2021/01/13)
Separation of racemic mixtures is of great importance and interest in chemistry and pharmacology. Porous materials including metal-organic frameworks (MOFs) have been widely explored as chiral stationary phases (CSPs) in chiral resolution. However, it remains a challenge to develop new CSPs for reversed-phase high-performance liquid chromatography (RP-HPLC), which is the most popular chromatographic mode and accounts for over 90% of all separations. Here we demonstrated for the first time that highly stable Zr-based MOFs can be efficient CSPs for RP-HPLC. By elaborately designing and synthesizing three tetracarboxylate ligands of enantiopure 1,1′-biphenyl-20-crown-6, we prepared three chiral porous Zr(IV)-MOFs with the framework formula [Zr6O4(OH)8(H2O)4(L)2]. They share the same flu topological structure but channels of different sizes and display excellent tolerance to water, acid, and base. Chiral crown ether moieties are periodically aligned within the framework channels, allowing for stereoselective recognition of guest molecules via supramolecular interactions. Under acidic aqueous eluent conditions, the Zr-MOF-packed HPLC columns provide high resolution, selectivity, and durability for the separation of a variety of model racemates, including unprotected and protected amino acids and N-containing drugs, which are comparable to or even superior to several commercial chiral columns for HPLC separation. DFT calculations suggest that the Zr-MOF provides a confined microenvironment for chiral crown ethers that dictates the separation selectivity.
Inherently chiral dialkyloxy-calix[4]arene acetic acids as enantiodiscriminating additives for high-performance liquid chromatography separation of d,l-amino acids
Kalchenko, Olga I.,Trybrat, Oleksandr O.,Yesypenko, Oleksandr A.,Dyakonenko, Viktoriya V.,Shishkina, Svitlana V.,Kalchenko, Vitali I.
, p. 722 - 730 (2021/08/26)
Inherently chiral dialkyloxy-calix[4]arene acetic acids with asymmetric placement of substituents on the lower rim of the macrocycle were first studied as enantiodiscriminating additives to the mobile phase MeCN/H2O/HCOOH (75/25/0.02 by volume) in the high-performance liquid chromatography (HPLC) separation of d,l-alanine and d,l-valine on the achiral stationary phase ZORBAX Original CN. The dependence of enantio-binding properties on the position of alkyl groups is demonstrated. The highest resolution (1.65) and enantioselectivity (1.80) were obtained for the 1,2-dipropyloxy-calix[4]arene acetic acid.
Direct monitoring of biocatalytic deacetylation of amino acid substrates by1H NMR reveals fine details of substrate specificity
De Cesare, Silvia,McKenna, Catherine A.,Mulholland, Nicholas,Murray, Lorna,Bella, Juraj,Campopiano, Dominic J.
supporting information, p. 4904 - 4909 (2021/06/16)
Amino acids are key synthetic building blocks that can be prepared in an enantiopure form by biocatalytic methods. We show that thel-selective ornithine deacetylase ArgE catalyses hydrolysis of a wide-range ofN-acyl-amino acid substrates. This activity was revealed by1H NMR spectroscopy that monitored the appearance of the well resolved signal of the acetate product. Furthermore, the assay was used to probe the subtle structural selectivity of the biocatalyst using a substrate that could adopt different rotameric conformations.
Mechanistic insight into metal ion-catalyzed transamination
Mayer, Robert J.,Kaur, Harpreet,Rauscher, Sophia A.,Moran, Joseph
supporting information, p. 19099 - 19111 (2021/11/22)
Several classes of biological reactions that are mediated by an enzyme and a co-factor can occur, to a slower extent, not only without the enzyme but even without the co-factor, under catalysis by metal ions. This observation has led to the proposal that metabolic pathways progressively evolved from using inorganic catalysts to using organocatalysts of increasing complexity. Transamination, the biological process by which ammonia is transferred between amino acids and α-keto acids, has a mechanism that has been well studied under enzyme/co-factor catalysis and under co-factor catalysis, but the metal ion-catalyzed variant was generally studied mostly at high temperatures (70-100 °C), and the details of its mechanism remained unclear. Here, we investigate which metal ions catalyze transamination under conditions relevant to biology (pH 7, 20-50 °C) and study the mechanism in detail. Cu2+, Ni2+, Co2+, and V5+ were identified as the most active metal ions under these constraints. Kinetic, stereochemical, and computational studies illuminate the mechanism of the reaction. Cu2+ and Co2+ are found to predominantly speed up the reaction by stabilizing a key imine intermediate. V5+ is found to accelerate the reaction by increasing the acidity of the bound imine. Ni2+ is found to do both to a limited extent. These results show that direct metal ion-catalyzed amino group transfer is highly favored even in the absence of co-factors or protein catalysts under biologically compatible reaction conditions.
