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Juli Wang, Haiying Yu, Kun Zhu
1-Alkenes are traditionally used as basic chemicals with great importance. Biosynthetic 1-alkenes also have the potential to serve as biofuels. In this study, we engineered a Pseudomonas lipolytic microbial platform for 1-alkene production using hydrophobic substrate as sole carbon source. Fatty acid decarboxylase UndA and UndB were cloned and expressed, which successfully produced 1-alkenes. Optimal culturing temperature and the interruption of competitive pathway were proven to be beneficial to 1-alkene synthesis...
May 1, 2018: Bioresource Technology
Revathi Masilamani, Melina B Cian, Zachary D Dalebroux
Salmonellae regulate membrane lipids during infection, but the exact proteins and mechanisms that promote their survival during bacteremia remain largely unknown. Mutations in genes encoding the conserved Salmonella enterica serovar Typhimurium (STm) Tol-Pal apparatus caused the outer-membrane (OM)-sensor lipoprotein, RcsF, to become activated. The capsule activation phenotype for the mutants suggested that Tol-Pal might influence envelope-lipid homeostasis. The mechanism involves reducing OM-glycerophospholipid (GPL) levels, since the mutant salmonellae similarly accumulated phosphatidylglycerols (PGl) and phosphatidylethanolamines (PE) compared to the wild type...
May 7, 2018: Infection and Immunity
Stephen Sarria, Thomas G Bartholow, Adam Verga, Michael D Burkart, Pamela Peralta-Yahya
Medium-chain fatty acids (MCFAs) are key intermediates in the synthesis of medium-chain chemicals including α-olefins and dicarboxylic acids. In bacteria, microbial production of MCFAs is limited by the activity and product profile of fatty acyl-ACP thioesterases. Here, we engineer a heterologous bacterial medium-chain fatty acyl-ACP thioesterase for improved MCFA production in Escherichia coli. Electrostatically matching the interface between the heterologous medium-chain Acinetobacter baylyi fatty acyl-ACP thioesterase (AbTE) and the endogenous E...
May 3, 2018: ACS Synthetic Biology
Wei Li, Aili Fan, Long Wang, Peng Zhang, Zhiguo Liu, Zhiqiang An, Wen-Bing Yin
Amino acid esters are a group of structurally diverse natural products with distinct activities. Some are synthesized through an inter-molecular esterification step catalysed by nonribosomal peptide synthetase (NRPS). In bacteria, the formation of the intra-molecular ester bond is usually catalysed by a thioesterase domain of NRPS. However, the mechanism by which fungal NRPSs perform this process remains unclear. Herein, by targeted gene disruption in Penicillium brevicompactum and heterologous expression in Aspergillus nidulans , we show that two NRPSs, ApmA and ApmB, are sufficient for the synthesis of an amino acid ester, asperphenamate...
March 7, 2018: Chemical Science
Joonwon Kim, Hee-Wang Yoo, Minsuk Kim, Eun-Jung Kim, Changmin Sung, Pyung-Gang Lee, Beom Gi Park, Byung-Gee Kim
ω-Hydroxy palmitic acid (ω-HPA) is a valuable compound for an ingredient of artificially synthesized ceramides and an additive for lubricants and adhesives. Production of such a fatty acid derivative is limited by chemical catalysis, but plausible by biocatalysis. However, its low productivity issue, including formations of unsaturated fatty acid (UFA) byproducts in host cells, remains as a hurdle toward industrial biological processes. In this study, to achieve selective and high-level production of ω-HPA from glucose in Escherichia coli, FadR, a native transcriptional regulator of fatty acid metabolism, and its regulon were engineered...
April 29, 2018: Metabolic Engineering
Mathias Brands, Vera Wewer, Andreas Keymer, Caroline Gutjahr, Peter Dörmann
Arbuscular mycorrhiza (AM) fungi establish symbiotic interactions with plants, providing the host plant with minerals, i.e. phosphate, in exchange with organic carbon. AM fungi of the Glominea produce vesicles, which store lipids as energy and carbon source. Acyl-acyl carrier protein (ACP) thioesterases (Fat) are essential components of the plant plastid-localized fatty acid synthase and determine the chain length of de novo synthesized fatty acids. In addition to the ubiquitous FatA and FatB thioesterases, AM-competent plants contain an additional, AM-specific FatM gene...
April 23, 2018: Plant Journal: for Cell and Molecular Biology
Rozana Rosli, Nadzirah Amiruddin, Mohd Amin Ab Halim, Pek-Lan Chan, Kuang-Lim Chan, Norazah Azizi, Priscilla E Morris, Eng-Ti Leslie Low, Meilina Ong-Abdullah, Ravigadevi Sambanthamurthi, Rajinder Singh, Denis J Murphy
Comparative genomics and transcriptomic analyses were performed on two agronomically important groups of genes from oil palm versus other major crop species and the model organism, Arabidopsis thaliana. The first analysis was of two gene families with key roles in regulation of oil quality and in particular the accumulation of oleic acid, namely stearoyl ACP desaturases (SAD) and acyl-acyl carrier protein (ACP) thioesterases (FAT). In both cases, these were found to be large gene families with complex expression profiles across a wide range of tissue types and developmental stages...
2018: PloS One
Huixin Lin, Hui Shen, Yuan K Lee
Metabolic engineering of microalgae to accumulate high levels of medium chain length fatty acids (MCFAs) has met with limited success. Traditional approaches employ single introduction of MCFA specific acyl-ACP thioesterases (TEs), but our current research in transgenic Dunaliella tertiolecta line has highlighted that, there is no single rate-limiting approach that can effectively increase MCFA levels. Here, we explore the accumulation of MCFAs in D. tertiolecta after transgenic expression of myristic acid biased TE (C14TE)...
2018: Frontiers in Microbiology
Rochelle Shirin Sadeghi, Katarzyna Kulej, Rahul Singh Kathayat, Benjamin A Garcia, Bryan C Dickinson, Donita C Brady, Eric Witze
Wnt5a has been implicated in melanoma progression and metastasis, although the exact downstream signaling events that contribute to melanoma metastasis are poorly understood. Wnt5a signaling results in acyl protein thioesterase 1 (APT1) mediated depalmitoylation of pro-metastatic cell adhesion molecules CD44 and MCAM, resulting in increased melanoma invasion. The mechanistic details that underlie Wnt5a-mediated regulation of APT1 activity and cellular function remain unknown. Here, we show Wnt5a signaling regulates APT1 activity through induction of APT1 phosphorylation and we further investigate the functional role of APT1 phosphorylation on its depalmitoylating activity...
April 12, 2018: ELife
Martin Klapper, Daniel Braga, Gerald Lackner, Rosa Herbst, Pierre Stallforth
Chemical and biochemical analyses of one of the most basic nonribosomal peptide synthetases (NRPS) from a Pseudomonas fluorescens strain revealed its striking plasticity. Determination of the potential substrate scope enabled us to anticipate novel secondary metabolites that could subsequently be isolated and tested for their bioactivities. Detailed analyses of the monomodular pyreudione synthetase showed that the biosynthesis of the bacterial pyreudione alkaloids does not require additional biosynthetic enzymes...
March 13, 2018: Cell Chemical Biology
Christopher M Goins, Thanuja D Sudasinghe, Xiaofan Liu, Yanping Wang, George A O'Doherty, Donald R Ronning
Tetrahydrolipstatin (THL) is a covalent inhibitor of many serine esterases. In mycobacteria, THL has been found to covalently react with 261 lipid esterases upon treatment of Mycobacterium bovis cell lysate. However, the covalent adduct is considered unstable in some cases due to the hydrolysis of the enzyme-linked THL adduct resulting in catalytic turnover. In this study, a library of THL stereo-derivatives was tested against three essential Mycobacterium tuberculosis lipid esterases of interest for drug development to assess how the stereochemistry of THL affects respective enzyme inhibition and allows for cross-enzyme inhibition...
March 30, 2018: Biochemistry
Rebecca S Kalinger, Ian P Pulsifer, Owen Rowland
Acyl-ACP thioesterase enzymes, which cleave fatty acyl thioester bonds to release free fatty acids, contribute to much of the fatty acid diversity in plants. In Arabidopsis thaliana, a family of four single hot-dog fold domain, plastid-localized acyl-lipid thioesterases (AtALT1-4) generate medium-chain (C6-C14) fatty and β-keto fatty acids as secondary metabolites. These volatile products may serve to attract insect pollinators or deter predatory insects. Homologs of AtALT1-4 are present in all plant taxa, but are nearly all uncharacterized...
March 13, 2018: Plant Physiology and Biochemistry: PPB
Michael W Beck, Rahul S Kathayat, Candace M Cham, Eugene B Chang, Bryan C Dickinson
The reversible modification of cysteine residues through thioester formation with palmitate (protein S -palmitoylation) is a prevalent chemical modification that regulates the function, localization, and stability of many proteins. Current methods for monitoring the "erasers" of S -palmitoylation, acyl-protein thioesterases (APTs), rely on destructive proteomic methods or "turn-on" probes, precluding deployment in heterogeneous samples such as primary tissues. To address these challenges, we present the design, synthesis, and biological evaluation of Ratiometric Depalmitoylation Probes (RDPs)...
November 1, 2017: Chemical Science
Fang Wang, Jingyi Wu, Zhichao Qiu, Xiaosong Ge, Xingxiang Liu, Chun Zhang, Wenhuan Xu, Fengming Wang, Dong Hua, Xiaowei Qi, Yong Mao
Acyl-CoA thioesterase 1 (ACOT1) is an important isoform of the ACOT family that catalyzes the reaction of fatty acyl-CoAs to CoA-SH and free fatty acids. Recent studies of gastrointestinal tumor metabolism suggest that there is abnormal metabolism of lipids and fatty acids during tumor progression. However, the function and contribution of ACOT1 in gastric cancer development are still poorly understood. Additionally, GLI3 is a major transcription factor in the regulation of hedgehog (Hh) signaling. GLI3 mutations induce glandular expansion and intestinal metaplasia in gastric cancer, which indicates a role for GLI3 in the preneoplastic process...
March 16, 2018: Human Pathology
Mariétou F Paye, Harrison B Rose, John M Robbins, Diana A Yunda, Seonggeon Cho, Andreas S Bommarius
Research involving α/β hydrolases, including α-amino acid ester hydrolase and cocaine esterase, has been limited by the lack of an online high throughput screening assay. The development of a high throughput screening assay capable of detecting α/β hydrolase activity toward specific substrates and/or chemical reactions (e.g., hydrolysis in lieu of amidase activity and/or synthesis instead of thioesterase activity) is of interest in a broad set of scientific questions and applications. Here we present a general framework for pH-based colorimetric assays, as well as the mathematical considerations necessary to estimate de novo the experimental response required to assign a 'hit' or a 'miss,' in the absence of experimental standard curves...
March 15, 2018: Analytical Biochemistry
Marika Ziesack, Nathan Rollins, Aashna Shah, Brendon Dusel, Gordon Webster, Pamela A Silver, Jeffrey C Way
Medium-chain fatty acids are commodity chemicals. Increasing and modifying the activity of thioesterases (TEs) on medium-chain fatty acyl-acyl carrier protein (acyl-ACP) esters may enable a high-yield microbial production of these molecules. The plant Cuphea palustris harbors two distinct TEs: C. palustris FatB1 ( Cp FatB1) (C8 specificity, lower activity) and Cp FatB2 (C14 specificity, higher activity) with 78% sequence identity. We combined structural features from these two enzymes to create several chimeric TEs, some of which showed nonnatural fatty acid production as measured by an enzymatic assay and gas chromatography-mass spectrometry (GC-MS)...
May 15, 2018: Applied and Environmental Microbiology
Jiangyong Gu, Li Li, Dongmei Wang, Wei Zhu, Ling Han, Ruizhi Zhao, Xiaojie Xu, Chuanjian Lu
OBJECTIVES: Psoriasis vulgaris is a chronic inflammatory and immune-mediated skin disease. 44 metabonomics biomarkers were identified by high-throughput liquid chromatography coupled to mass spectrometry in our previous work, but the roles of metabonomics biomarkers in the pathogenesis of psoriasis is unclear. METHODS: The metabonomics biomarker-enzyme network was constructed. The key metabonomics biomarkers and enzymes were screened out by network analysis. The binding affinity between each metabonomics biomarker and target was calculated by molecular docking...
June 2018: Annals of Medicine
Fuyuan Jing, Le Zhao, Marna D Yandeau-Nelson, Basil J Nikolau
The substrate specificity of acyl-ACP thioesterase (TE) plays an essential role in controlling the fatty acid profile produced by type II fatty acid synthases. Here we identify two groups of residues that synergistically determine different substrate specificities of two acyl-ACP TEs from Cuphea viscosissima (CvFatB1 and CvFatB2). One group (V194, V217, N223, R226, R227, and I268 in CvFatB2) is critical in determining the structure and depth of a hydrophobic cavity in the N-terminal hotdog domain that binds the substrate's acyl moiety...
February 28, 2018: Nature Communications
Yanbin Feng, Yunxiu Zhang, Yayue Wang, Jiao Liu, Yinghui Liu, Xupeng Cao, Song Xue
Medium-chain fatty acids have attracted significant attention as sources of biofuels in recent years. Acyl-ACP thioesterase, which is considered as the key enzyme to determine the carbon chain length, catalyzes the termination of de novo fatty acid synthesis. Although recombinant medium-chain acyl-ACP thioesterase (TE) affects the fatty acid profile in heterologous cells, tailoring of the fatty acid composition merely by engineering a specific TE is still intractable. In this study, the activity of a C8-C10-specific thioesterase FatB2 from Cuphea hookeriana on C10-ACP was quantified twice as high as that on C8-ACP based on a synthetic C8-C16 acyl-ACP pool in vitro...
April 2018: Applied Microbiology and Biotechnology
Kang Xiao, Xiu-Hong Yue, Wen-Chao Chen, Xue-Rong Zhou, Lian Wang, Lin Xu, Feng-Hong Huang, Xia Wan
Medium chain hydroxy fatty acids (HFAs) at ω-1, 2, or 3 positions (ω-1/2/3) are rare in nature but are attractive due to their potential applications in industry. They can be metabolically engineered in Escherichia coli , however, the current yield is low. In this study, metabolic engineering with P450BM3 monooxygenase was applied to regulate both the chain length and sub-terminal position of HFA products in E. coli , leading to increased yield. Five acyl-acyl carrier protein thioesterases from plants and bacteria were first evaluated for regulating the chain length of fatty acids...
2018: Frontiers in Microbiology
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