Application of directed evolution in the development of enantioselective enzymes

2000 ◽  
Vol 72 (9) ◽  
pp. 1615-1622 ◽  
Author(s):  
Manfred T. Reetz
Keyword(s):  
Organic Chemistry ◽  
Gene Expression ◽  
High Throughput ◽  
High Throughput Screening ◽  
Kinetic Resolution ◽  
Random Mutagenesis ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Hydrolytic Kinetic Resolution ◽  
Novel Approach

A novel approach to developing enantioselective enzymes for use in organic chemistry has been devised which is independent of structural or mechanistic aspects. The underlying idea is to combine appropriate methods of random mutagenesis, gene expression, and high-throughput screening for enantioselectivity. If these actions are performed in repetitive cycles, an evolutionary pressure is created that leads to sequential improvements of the enantioselectivity of a given enzyme-catalyzed reaction. The concept is illustrated by an example involving the lipase-catalyzed hydrolytic kinetic resolution of an α-chiral ester, the enantio-selectivity increasing from ee = 2% (E =1.1) for a wild-type enzyme to ee = 90-93% (E = 25) for the best mutants.

Directed Evolution of P450 Fatty Acid Decarboxylases via High-Throughput Screening Towards Improved Catalytic Activity

2019 ◽  
Author(s):  
Huifang Xu ◽  
Weinan Liang ◽  
Linlin Ning ◽  
Yuanyuan Jiang ◽  
Wenxia Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fatty Acid ◽  
Directed Evolution ◽  
High Throughput ◽  
High Throughput Screening ◽  
Colorimetric Detection ◽  
Screening Method ◽  
Random Mutagenesis ◽  
Direct Production ◽  
Consumption Activity

P450 fatty acid decarboxylases (FADCs) have recently been attracting considerable attention owing to their one-step direct production of industrially important 1-alkenes from biologically abundant feedstock free fatty acids under mild conditions. However, attempts to improve the catalytic activity of FADCs have met with little success. Protein engineering has been limited to selected residues and small mutant libraries due to lack of an effective high-throughput screening (HTS) method. Here, we devise a catalase-deficient <i>Escherichia coli</i> host strain and report an HTS approach based on colorimetric detection of H<sub>2</sub>O<sub>2</sub>-consumption activity of FADCs. Directed evolution enabled by this method has led to effective identification for the first time of improved FADC variants for medium-chain 1-alkene production from both DNA shuffling and random mutagenesis libraries. Advantageously, this screening method can be extended to other enzymes that stoichiometrically utilize H<sub>2</sub>O<sub>2</sub> as co-substrate.

scholarly journals High-Throughput Screening for CEBPD-Modulating Compounds in THP-1-Derived Reporter Macrophages Identifies Anti-Inflammatory HDAC and BET Inhibitors

2021 ◽  
Vol 22 (6) ◽  
pp. 3022
Author(s):  
Tatjana Ullmann ◽  
Sonja Luckhardt ◽  
Markus Wolf ◽  
Michael J. Parnham ◽  
Eduard Resch
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
High Throughput ◽  
Transcription Initiation ◽  
High Throughput Screening ◽  
Inflammatory Responses ◽  
Hdac Inhibitors ◽  
Screening Assay ◽  
Bet Inhibitors ◽  
Anti Inflammatory

This study aimed to identify alternative anti-inflammatory compounds that modulate the activity of a relevant transcription factor, CCAAT/enhancer binding protein delta (C/EBPδ). C/EBPδ is a master regulator of inflammatory responses in macrophages (Mϕ) and is mainly regulated at the level of CEBPD gene transcription initiation. To screen for CEBPD-modulating compounds, we generated a THP-1-derived reporter cell line stably expressing secreted alkaline phosphatase (SEAP) under control of the defined CEBPD promoter (CEBPD::SEAP). A high-throughput screening of LOPAC®1280 and ENZO®774 libraries on LPS- and IFN-γ-activated THP-1 reporter Mϕ identified four epigenetically active hits: two bromodomain and extraterminal domain (BET) inhibitors, I-BET151 and Ro 11-1464, as well as two histone deacetylase (HDAC) inhibitors, SAHA and TSA. All four hits markedly and reproducibly upregulated SEAP secretion and CEBPD::SEAP mRNA expression, confirming screening assay reliability. Whereas BET inhibitors also upregulated the mRNA expression of the endogenous CEBPD, HDAC inhibitors completely abolished it. All hits displayed anti-inflammatory activity through the suppression of IL-6 and CCL2 gene expression. However, I-BET151 and HDAC inhibitors simultaneously upregulated the mRNA expression of pro-inflammatory IL-1ß. The modulation of CEBPD gene expression shown in this study contributes to our understanding of inflammatory responses in Mϕ and may offer an approach to therapy for inflammation-driven disorders.

scholarly journals Erratum: Corrigendum: Gene expression–based high-throughput screening (GE-HTS) and application to leukemia differentiation

2004 ◽  
Vol 36 (4) ◽  
pp. 427-427 ◽  
Author(s):  
K Stegmaier ◽  
K N Ross ◽  
S A Colavito ◽  
S O'Malley ◽  
B R Stockwell ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Throughput ◽  
High Throughput Screening

scholarly journals Hydrogen overproducing nitrogenases obtained by random mutagenesis and high-throughput screening

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Emma Barahona ◽  
Emilio Jiménez-Vicente ◽  
Luis M. Rubio
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Rhodobacter Capsulatus ◽  
Random Mutagenesis ◽  
Fluorescence Emission ◽  
Inducible Promoter ◽  
Hydrogen Gas ◽  
Photosynthetic Organisms ◽  
Fe Protein ◽  
Protein Variants

Abstract When produced biologically, especially by photosynthetic organisms, hydrogen gas (H2) is arguably the cleanest fuel available. An important limitation to the discovery or synthesis of better H2-producing enzymes is the absence of methods for the high-throughput screening of H2 production in biological systems. Here, we re-engineered the natural H2 sensing system of Rhodobacter capsulatus to direct the emission of LacZ-dependent fluorescence in response to nitrogenase-produced H2. A lacZ gene was placed under the control of the hupA H2-inducible promoter in a strain lacking the uptake hydrogenase and the nifH nitrogenase gene. This system was then used in combination with fluorescence-activated cell sorting flow cytometry to screen large libraries of nitrogenase Fe protein variants generated by random mutagenesis. Exact correlation between fluorescence emission and H2 production levels was found for all automatically selected strains. One of the selected H2-overproducing Fe protein variants lacked 40% of the wild-type amino acid sequence, a surprising finding for a protein that is highly conserved in nature. We propose that this method has great potential to improve microbial H2 production by allowing powerful approaches such as the directed evolution of nitrogenases and hydrogenases.

scholarly journals In Vivo, High-Throughput Selection of Thermostable Cyclohexanone Monooxygenase (CHMO)

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 935
Author(s):  
Sarah Maxel ◽  
Linyue Zhang ◽  
Edward King ◽  
Ana Paula Acosta ◽  
Ray Luo ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Rational Design ◽  
Random Mutagenesis ◽  
Residual Activity ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Coli Strain ◽  
Screening Tools ◽  
Cyclohexanone Monooxygenase

Cyclohexanone monooxygenase (CHMO) from Acinetobacter sp. NCIMB 9871 is characterized as having wide substrate versatility for the biooxidation of (cyclic) ketones into esters and lactones with high stereospecificity. Despite industrial potential, CHMO usage is restricted by poor thermostability. Limited high-throughput screening tools and challenges in rationally engineering thermostability have impeded CHMO engineering efforts. We demonstrate the application of an aerobic, high-throughput growth selection platform in Escherichia coli (strain MX203) for the discovery of thermostability enhancing mutations for CHMO. The selection employs growth for the easy readout of CHMO activity in vivo, by requiring nicotinamide adenine dinucleotide phosphate (NADPH)-consuming enzymes to restore cellular redox balance. In the presence of the native substrate cyclohexanone, variant CHMO GV (A245G-A288V) was discovered from a random mutagenesis library screened at 42 °C. This variant retained native activity, exhibited ~4.4-fold improvement in residual activity after 30 °C incubation, and demonstrated ~5-fold higher cyclohexanone conversion at 37 °C compared to the wild type. Molecular modeling indicates that CHMO GV experiences more favorable residue packing and supports additional backbone hydrogen bonding. Further rational design resulted in CHMO A245G-A288V-T415C with improved thermostability at 45 °C. Our platform for oxygenase evolution enabled the rapid engineering of protein stability critical for industrial scalability.

scholarly journals Erratum: Corrigendum: Gene expression–based high-throughput screening (GE-HTS) and application to leukemia differentiation

2005 ◽  
Vol 37 (3) ◽  
pp. 328-328
Author(s):  
K Stegmaier ◽  
K N Ross ◽  
S A Colavito ◽  
S O'Malley ◽  
B R Stockwell ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Throughput ◽  
High Throughput Screening

scholarly journals Synergistic benefit in inflammatory arthritis by targeting IκB kinase ϵ and interferon β

2008 ◽  
Vol 68 (2) ◽  
pp. 257-263 ◽  
Author(s):  
M Corr ◽  
D L Boyle ◽  
L Ronacher ◽  
N Flores ◽  
G S Firestein
Keyword(s):  
Gene Expression ◽  
Low Dose ◽  
Serum Levels ◽  
Poly I:C ◽  
Type I ◽  
Wild Type ◽  
Polycytidylic Acid ◽  
Iκb Kinase ◽  
Novel Approach ◽  
Clinical Arthritis

Objectives:The IκB kinase (IKK)-related kinase IKKϵ regulates type I interferon expression and responses as well as proinflammatory mediator production. We examined the role of IKKϵ in arthritis and its ability to enhance the therapeutic response to systemic interferon (IFN) β therapy in passive murine K/BxN arthritis.Methods:IKKϵ–/–, IFNα∼βR–/– and wild type mice were given K/BxN serum and treated with polyinosinic polycytidylic acid (poly(I:C)), IFNβ, or normal saline. Clinical response and histological scores were assessed. Gene expression in the paws was measured by quantitative PCR. Serum interleukin 1a receptor agonist (IL1Ra) and IL10 were measured by ELISA and multiplex bead array.Results:Arthritis was almost completely blocked in wild type mice if arthritogenic K/BxN serum and the Toll-like receptor (TLR)3 ligand, poly(I:C), were coadministered at the onset of the model, but not in established disease. Mice deficient in IFNα∼βR had an accelerated course of arthritis, and did not respond to poly(I:C). IKKϵ null mice had a modest decrease in clinical arthritis compared with heterozygous mice. Low doses of IFNβ that were ineffective in wild type mice significantly decreased clinical arthritis in IKKϵ null mice. Articular chemokine gene expression was reduced in the IKKϵ–/– mice with arthritis and secreted IL1Ra (sIL1Ra) mRNA was significantly increased. Serum levels of IL1Ra were increased in low dose IFNβ-treated IKKϵ–/– mice.Conclusions:Subtherapeutic doses of IFNβ enhance the anti-inflammatory effects of IKKϵ deficiency, possibly by increasing production of IL1Ra and unmasking the antichemokine effects. Combination therapy with low dose IFNβ and an IKKϵ inhibitor might improve efficacy of either agent alone and offers a novel approach to RA.

scholarly journals Genomic Profiling of Iron-Responsive Genes in Salmonella enterica Serovar Typhimurium by High-Throughput Screening of a Random Promoter Library

2003 ◽  
Vol 185 (16) ◽  
pp. 4973-4982 ◽  
Author(s):  
Jaime Bjarnason ◽  
Carolyn M. Southward ◽  
Michael G. Surette
Keyword(s):  
Gene Expression ◽  
High Throughput ◽  
Salmonella Enterica ◽  
High Throughput Screening ◽  
Expression Profiles ◽  
Transport Systems ◽  
Iron Availability ◽  
Iron Storage ◽  
Promoter Library ◽  
Serovar Typhimurium

ABSTRACT The importance of iron to bacteria is shown by the presence of numerous iron-scavenging and transport systems and by many genes whose expression is tightly regulated by iron availability. We have taken a global approach to gene expression analysis of Salmonella enterica serovar Typhimurium in response to iron by combining efficient, high-throughput methods with sensitive, luminescent reporting of gene expression using a random promoter library. Real-time expression profiles of the library were generated under low- and high-iron conditions to identify iron-regulated promoters, including a number of previously identified genes. Our results indicate that approximately 7% of the genome may be regulated directly or indirectly by iron. Further analysis of these clones using a Fur titration assay revealed three separate classes of genes; two of these classes consist of Fur-regulated genes. A third class was Fur independent and included both negatively and positively iron-responsive genes. These may reflect new iron-dependent regulons. Iron-responsive genes included iron transporters, iron storage and mobility proteins, iron-containing proteins (redox proteins, oxidoreductases, and cytochromes), transcriptional regulators, and the energy transducer tonB. By identifying a wide variety of iron-responsive genes, we extend our understanding of the global effect of iron availability on gene expression in the bacterial cell.

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