| 1. |
- Asgari, Parham, et al.
(författare)
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Catalytic hydrogen atom transfer from hydrosilanes to vinylarenes for hydrosilylation and polymerization
- 2019
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Ingår i: Nature Catalysis. - : Nature Publishing Group. - 2520-1158. ; 2:2, s. 164-173
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Tidskriftsartikel (refereegranskat)abstract
- Because of the importance of hydrogen atom transfer (HAT) in biology and chemistry, there is increased interest in new strategies to perform HAT in a sustainable manner. Here, we describe a sustainable, net redox-neutral HAT process involving hydrosilanes and alkali metal Lewis base catalysts-eliminating the use of transition metal catalysts-and report an associated mechanism concerning Lewis base-catalysed, complexation-induced HAT. The catalytic Lewis base-catalysed, complexation-induced HAT is capable of accessing both branch-specific hydrosilylation and polymerization of vinylarenes in a highly selective fashion, depending on the Lewis base catalyst used. In this process, the Earth-abundant, alkali metal Lewis base catalyst plays a dual role. It first serves as a HAT initiator and subsequently functions as a silyl radical stabilizing group, which is critical to highly selective cross-radical coupling. An electron paramagnetic resonance study identified a potassiated paramagnetic species, and multistate density functional theory revealed a high HAT character, yet multiconfigurational nature in the transition state of the reaction.
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| 2. |
- Janasch, Markus, et al.
(författare)
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CO2 fixation gets a second chance
- 2021
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Ingår i: NATURE CATALYSIS. - : Springer Nature. - 2520-1158. ; 4:2, s. 94-95
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Li, Feiran, 1993, et al.
(författare)
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Deep learning-based k(cat) prediction enables improved enzyme-constrained model reconstruction
- 2022
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 5:8, s. 662-672
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Tidskriftsartikel (refereegranskat)abstract
- Enzyme turnover numbers (k(cat)) are key to understanding cellular metabolism, proteome allocation and physiological diversity, but experimentally measured k(cat) data are sparse and noisy. Here we provide a deep learning approach (DLKcat) for high-throughput k(cat) prediction for metabolic enzymes from any organism merely from substrate structures and protein sequences. DLKcat can capture k(cat) changes for mutated enzymes and identify amino acid residues with a strong impact on k(cat) values. We applied this approach to predict genome-scale k(cat) values for more than 300 yeast species. Additionally, we designed a Bayesian pipeline to parameterize enzyme-constrained genome-scale metabolic models from predicted k(cat) values. The resulting models outperformed the corresponding original enzyme-constrained genome-scale metabolic models from previous pipelines in predicting phenotypes and proteomes, and enabled us to explain phenotypic differences. DLKcat and the enzyme-constrained genome-scale metabolic model construction pipeline are valuable tools to uncover global trends of enzyme kinetics and physiological diversity, and to further elucidate cellular metabolism on a large scale.
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| 4. |
- Li, Xiaowei, 1986, et al.
(författare)
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Metabolic network remodelling enhances yeast’s fitness on xylose using aerobic glycolysis
- 2021
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 4:9, s. 783-796
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Tidskriftsartikel (refereegranskat)abstract
- The reprogramming of metabolism in response to switching the carbon source from glucose to non-preferred carbon sources is well-studied for yeast. However, understanding how metabolic networks respond to utilize a non-natural carbon source such as xylose is limited due to the incomplete knowledge of cellular response mechanisms. Here we applied a combination of metabolic engineering, systems biology and adaptive laboratory evolution to gain insights into how yeast can perform a global rewiring of cellular processes to efficiently accompany metabolic transitions. Through metabolic engineering, we substantially enhanced the cell growth on xylose after the growth on glucose. Transcriptome analysis of the engineered strains demonstrated that multiple pathways were involved in the cellular reprogramming. Through genome resequencing of the evolved strains and reverse engineering, we further identified that SWI/SNF chromatin remodelling, osmotic response and aldehyde reductase were responsible for the improved growth. Combined, our analysis showed that glycerol-3-phosphate and xylitol serve as two key metabolites that affect cellular adaptation to growth on xylose. [Figure not available: see fulltext.].
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| 5. |
- Liu, Jianguo, et al.
(författare)
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Iridium-catalysed asymmetric hydrogenation of allylic alcohols via dynamic kinetic resolution
- 2018
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 1:6, s. 438-443
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic kinetic resolutions (DKRs) allow for the conversion of both enantiomers of starting material into a single enantiomer of product, hence avoiding the 50% yield limit observed in traditional kinetic resolutions. Transition-metal-catalysed variants have become an important and useful method in asymmetric synthesis. Here we report an asymmetric hydrogenation of allylic alcohols using an Ir–N,P-ligand complex via DKR. In contrast to the many DKRs involving carbonyl reduction, this methodology allows for DKR during alkene reduction. Mechanistic studies support the hypothesis that racemization of the substrate is achieved by cleavage and reforming of the oxygen–carbon bond. Under the cooperative dynamic kinetic asymmetric hydrogenation, a broad range of chiral alcohols containing two stereogenic centres were produced with excellent diastereoselectivities (up to 95:5) and enantioselectivities (up to 99%).
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| 6. |
- Liu, Zihe, et al.
(författare)
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Third-generation biorefineries as the means to produce fuels and chemicals from CO2
- 2020
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 3:3, s. 274-288
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Forskningsöversikt (refereegranskat)abstract
- Concerns regarding petroleum depletion and global climate change caused by greenhouse gas emissions have spurred interest in renewable alternatives to fossil fuels. Third-generation (3G) biorefineries aim to utilize microbial cell factories to convert renewable energies and atmospheric CO2 into fuels and chemicals, and hence represent a route for assessing fuels and chemicals in a carbon-neutral manner. However, to establish processes competitive with the petroleum industry, it is important to clarify/evaluate/identify the most promising CO2 fixation pathways, the most appropriate CO2 utilization models and the necessary productivity levels. Here, we discuss the latest advances in 3G biorefineries. Following an overview of applications of CO2 feedstocks, mainly from flue gas and waste gasification, we review prominent opportunities and barriers in CO2 fixation and energy capture. We then summarize reported CO2-based products and industries, and describe trends and key challenges for future advancement of 3G biorefineries. A shift from sugar-based feedstocks and biomass to the use of atmospheric CO2 for the bioproduction of fuels and chemicals is desirable. This Review describes how microorganisms can be engineered for CO2 fixation and industrial valorization of this key molecule.
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| 7. |
- Qin, Jiufu, 1985, et al.
(författare)
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Engineering yeast metabolism for the discovery and production of polyamines and polyamine analogues
- 2021
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 4:6, s. 498-509
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Tidskriftsartikel (refereegranskat)abstract
- Structurally complex and diverse polyamines and polyamine analogues are potential therapeutics and agrochemicals that can address grand societal challenges, for example, healthy ageing and sustainable food production. However, their structural complexity and low abundance in nature hampers either bulk chemical synthesis or extraction from natural resources. Here we reprogrammed the metabolism of baker’s yeast Saccharomyces cerevisiae and recruited nature’s diverse reservoir of biochemical tools to enable a complete biosynthesis of multiple polyamines and polyamine analogues. Specifically, we adopted a systematic engineering strategy to enable gram-per-litre-scale titres of spermidine, a central metabolite in polyamine metabolism. To demonstrate the potential of our polyamine platform, various polyamine synthases and ATP-dependent amide-bond-forming systems were introduced for the biosynthesis of natural and unnatural polyamine analogues. The yeast platform serves as a resource to accelerate the discovery and production of polyamines and polyamine analogues, and thereby unlocks this chemical space for further pharmacological and insecticidal studies. [Figure not available: see fulltext.]
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| 8. |
- Shatskiy, Andrey, et al.
(författare)
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Electrifying catalytic aerobic oxidation
- 2021
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Ingår i: NATURE CATALYSIS. - : Springer Nature. - 2520-1158. ; 4:2, s. 96-97
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Shin, Jae Ho, 1987
(författare)
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A comprehensive metabolic map for production of bio-based chemicals
- 2019
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 2:1, s. 18-33
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Forskningsöversikt (refereegranskat)abstract
- Production of industrial chemicals using renewable biomass feedstock is becoming increasingly important to address limited fossil resources, climate change and other environmental problems. To develop high-performance microbial cell factories, equivalent to chemical plants, microorganisms undergo systematic metabolic engineering to efficiently convert biomass-derived carbon sources into target chemicals. Over the past two decades, many engineered microorganisms capable of producing natural and non-natural chemicals have been developed. This Review details the current status of representative industrial chemicals that are produced through biological and/or chemical reactions. We present a comprehensive bio-based chemicals map that highlights the strategies and pathways of single or multiple biological reactions, chemical reactions and combinations thereof towards production of particular chemicals of interest. Future challenges are also discussed to enable production of even more diverse chemicals and more efficient production of chemicals from renewable feedstocks
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| 10. |
- Wang, Aiyong, 1989, et al.
(författare)
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The impact of automotive catalysis on the United Nations sustainable development goals
- 2019
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 2:7, s. 566-570
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Catalysis is essential in the automotive and transportation sectors to target the United Nations sustainable development goals for climate change and the environment. To comply with both the ambitious United Nations goals and step-by-step stringent emission regulations, innovative and economically viable catalytic systems will be a key element in meeting these challenges.
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| 11. |
- Yang, Hao, et al.
(författare)
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Intramolecular hydroxyl nucleophilic attack pathway by a polymeric water oxidation catalyst with single cobalt sites
- 2022
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Ingår i: Nature Catalysis. - : Springer Nature. - 2520-1158. ; 5:5, s. 414-429
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Tidskriftsartikel (refereegranskat)abstract
- Exploration of efficient water oxidation catalysts (WOCs) is the primary challenge in conversion of renewable energy into fuels. Here we report a molecularly well-defined heterogeneous WOC with Aza-fused, pi-conjugated, microporous polymer (Aza-CMP) coordinated single cobalt sites (Aza-CMP-Co). The single cobalt sites in Aza-CMP-Co exhibited superior activity under alkaline and near-neutral conditions. Moreover, the molecular nature of the isolated catalytic sites makes Aza-CMP-Co a reliable model for studying the heterogeneous water oxidation mechanism. By a combination of experimental and theoretical results, a pH-dependent nucleophilic attack pathway for O-O bond formation was proposed. Under alkaline conditions, the intramolecular hydroxyl nucleophilic attack (IHNA) process with which the adjacent -OH group nucleophilically attacks Co4+=O was identified as the rate-determining step. This process leads to lower activation energy and accelerated kinetics than those of the intermolecular water nucleophilic attack (WNA) pathway. This study provides significant insights into the crucial function of electrolyte pH in water oxidation catalysis and enhancement of water oxidation activity by regulation of the IHNA pathway.
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| 12. |
- Zhan, Chunjun, 1986, et al.
(författare)
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Reprogramming methanol utilization pathways to convert Saccharomyces cerevisiae to a synthetic methylotroph
- 2023
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Ingår i: Nature Catalysis. - 2520-1158. ; 6:5, s. 435-450
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Tidskriftsartikel (refereegranskat)abstract
- Methanol, an organic one-carbon (C1) compound, represents an attractive alternative carbon source for microbial fermentation. Despite considerable advancements in methanol utilization by prokaryotes such as Escherichia coli, engineering eukaryotic model organisms such as Saccharomyces cerevisiae into synthetic methylotrophs remains challenging. Here, an engineered module circuit strategy combined with adaptive laboratory evolution was applied to engineer S. cerevisiae to use methanol as the sole carbon source. We revealed that the evolved glyoxylate-based serine pathway plays an important role in methanol-dependent growth by promoting formaldehyde assimilation. Further, we determined that the isoprenoid biosynthetic pathway was upregulated, resulting in an increased concentration of squalene and ergosterol in our evolved strain. These changes could potentially alleviate cell membrane damage in the presence of methanol. This work sets the stage for expanding the potential of exploiting S. cerevisiae as a potential organic one-carbon platform for biochemical or biofuel production. [Figure not available: see fulltext.].
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| 13. |
- Zheng, Jia, et al.
(författare)
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Iridium-catalysed enantioselective formal deoxygenation of racemic alcohols via asymmetric hydrogenation
- 2019
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Ingår i: NATURE CATALYSIS. - : NATURE PUBLISHING GROUP. - 2520-1158. ; 2:12, s. 1093-1100
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Tidskriftsartikel (refereegranskat)abstract
- Asymmetric hydrogenation of alkenes is one of the most powerful tools for the preparation of optically active compounds. However, to achieve high enantioselectivity, the starting olefin in most cases needs to be isomerically pure in either the cis or the trans form. Generally, most olefination protocols provide olefins as isomeric mixtures that are difficult to separate, and in many cases also generate lots of waste. In contrast, the synthesis of racemic alcohols is straightforward and highly atom-efficient, with products that are easier to purify. Here, we describe a strategy that enables rapid access to chiral alkanes via enantioconvergent formal deoxygenation of racemic alcohols. Mechanistic studies indicate an Ir-mediated elimination of water and subsequent in situ hydrogenation. This approach allows rapid and efficient assembly of chiral intermediates and is exemplified in the total synthesis of antidepressant sertraline and sigma(2) receptor PB 28.
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| 14. |
- Zhiwei, Zhu, 1985, et al.
(författare)
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Multidimensional engineering of Saccharomyces cerevisiae for efficient synthesis of medium-chain fatty acids
- 2020
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Ingår i: Nature Catalysis. - : Springer Science and Business Media LLC. - 2520-1158. ; 3:1, s. 64-74
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Tidskriftsartikel (refereegranskat)abstract
- Medium-chain fatty acids (MCFAs; C6–C12) are valuable molecules used for biofuel and oleochemical production; however, it is challenging to synthesize these fatty acids efficiently using microbial biocatalysts due to the cellular toxicity of MCFAs. In this study, both the endogenous fatty acid synthase (FAS) and an orthogonal bacterial type I FAS were engineered for MCFA production in the yeast Saccharomyces cerevisiae. To improve cellular tolerance to toxic MCFAs, we performed directed evolution of the membrane transporter Tpo1 and strain adaptive laboratory evolution, which elevated the MCFA production by 1.3 ± 0.3- and 1.7 ± 0.2-fold, respectively. We therefore further engineered the highly resistant strain to augment the metabolic flux towards MCFAs. This multidimensional engineering of the yeast at the single protein/enzyme level, the pathway level and the cellular level, combined with an optimized cultivation process, resulted in the production of >1 g l−1 extracellular MCFAs—a more than 250-fold improvement over the original strain.
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