scholarly journals Synthesis of three major auxins from glucose in EngineeredEscherichia coli

2018 ◽  
Author(s):  
Daoyi Guo ◽  
Lihua Zhang ◽  
Sijia Kong ◽  
Zhijie Liu ◽  
Xu Chu ◽  
...  
Keyword(s):  
Plant Growth ◽  
Phenylacetic Acid ◽  
De Novo ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Plant Growth And Development ◽  
E Coli ◽  
Naturally Occurring ◽  
Hydroxyphenylacetic Acid ◽  
Indole 3 Acetic Acid

ABSTRACTIndole-3-acetic acid (IAA) is considered the most common and important naturally occurring auxin in plants and a major regulator of plant growth and development. In addition, phenylacetic acid (PAA) and 4-hydroxyphenylacetic acid (4HPA) can also play a role as auxin in some plants. In recent years, several microbes have been metabolically engineered to produce IAA from L-tryptophan. In this study, we showed that aminotransferasearo8and decarboxylasekdcfromSaccharomyces cerevisiae, and aldehyde dehydrogenasealdHfromEscherichia colihave broad substrate ranges and can catalyze the conversion of three kinds of aromatic amino acids (L-tryptophan, L-tyrosine or L-phenylalanine) to the corresponding IAA, 4HPA and PAA. Subsequently, three de novo biosynthetic pathways for the production of IAA, PAA and 4HPA from glucose were constructed inE. colithrough strengthening the shikimate pathway. This study described here shows the way for the development of agricultural microorganism for biosynthesis of plant auxin and promoting plant growth in the future.

scholarly journals Ruminal bioshynthesis of aromatic amino acids from arylacetic acids, glucose, shikimic acid and phenol

1974 ◽  
Vol 31 (3) ◽  
pp. 357-365 ◽  
Author(s):  
S. Kristensen
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Phenylacetic Acid ◽  
Shikimic Acid ◽  
Aromatic Amino Acids ◽  
Hydroxyphenylacetic Acid ◽  
Arylacetic Acids ◽  
First Time ◽  
Indole 3 Acetic Acid

1. Ruminal metabolism of labelled phenylacetic acid, 4-hydroxyphenylacetic acid, indole-3-acetic acid, glucose, shikimic acid, phenol, and serine was studied in vitro by short-term incubation with special reference to incorporation rates into aromatic amino acids.2. Earlier reports on reductive carboxylation of phenylacetic acid and indole-3-acetic acid in the rumen were confirmed and the formation of tyrosine from 4-hydroxyphenylacetic acid was demonstrated for the first time.3. The amount of phenylalanine synthesized from phenylacetic acid was estimated to be 2 mg/1 rumen contents per 24 h, whereas the amount synthesized from glucose might be eight times as great, depending on diet.4. Shikimic acid was a poor precursor of the aromatic amino acids, presumably owing to its slow entry into rumen bacteria.5. A slow conversion of phenol into tyrosine was observed.

scholarly journals Production of Aromatic Compounds by Metabolically Engineered Escherichia coli with an Expanded Shikimate Pathway

2012 ◽  
Vol 78 (17) ◽  
pp. 6203-6216 ◽  
Author(s):  
Daisuke Koma ◽  
Hayato Yamanaka ◽  
Kunihiko Moriyoshi ◽  
Takashi Ohmoto ◽  
Kiyofumi Sakai
Keyword(s):  
Escherichia Coli ◽  
Aromatic Compounds ◽  
Phenylacetic Acid ◽  
Shikimate Pathway ◽  
Phenyllactic Acid ◽  
Content Type ◽  
E Coli ◽  
Dehydrogenase Gene ◽  
Hydroxyphenylacetic Acid ◽  
By Products

ABSTRACTEscherichia coliwas metabolically engineered by expanding the shikimate pathway to generate strains capable of producing six kinds of aromatic compounds, phenyllactic acid, 4-hydroxyphenyllactic acid, phenylacetic acid, 4-hydroxyphenylacetic acid, 2-phenylethanol, and 2-(4-hydroxyphenyl)ethanol, which are used in several fields of industries including pharmaceutical, agrochemical, antibiotic, flavor industries, etc. To generate strains that produce phenyllactic acid and 4-hydroxyphenyllactic acid, the lactate dehydrogenase gene (ldhA) fromCupriavidus necatorwas introduced into the chromosomes of phenylalanine and tyrosine overproducers, respectively. Both the phenylpyruvate decarboxylase gene (ipdC) fromAzospirillum brasilenseand the phenylacetaldehyde dehydrogenase gene (feaB) fromE. coliwere introduced into the chromosomes of phenylalanine and tyrosine overproducers to generate phenylacetic acid and 4-hydroxyphenylacetic acid producers, respectively, whereasipdCand the alcohol dehydrogenase gene (adhC) fromLactobacillus breviswere introduced to generate 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, respectively. Expression of the respective introduced genes was controlled by the T7 promoter. While generating the 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol producers, we found that produced phenylacetaldehyde and 4-hydroxyphenylacetaldehyde were automatically reduced to 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol by endogenous aldehyde reductases inE. coliencoded by theyqhD,yjgB, andyahKgenes. Cointroduction and cooverexpression of each gene withipdCin the phenylalanine and tyrosine overproducers enhanced the production of 2-phenylethanol and 2-(4-hydroxyphenyl)ethanol from glucose. Introduction of theyahKgene yielded the most efficient production of both aromatic alcohols. During the production of 2-phenylethanol, 2-(4-hydroxyphenyl)ethanol, phenylacetic acid, and 4-hydroxyphenylacetic acid, accumulation of some by-products were observed. Deletion offeaB,pheA, and/ortyrAgenes from the chromosomes of the constructed strains resulted in increased desired aromatic compounds with decreased by-products. Finally, each of the six constructed strains was able to successfully produce a different aromatic compound as a major product. We show here that six aromatic compounds are able to be produced from renewable resources without supplementing with expensive precursors.

scholarly journals GH3 Auxin-Amido Synthetases Alter the Ratio of Indole-3-Acetic Acid and Phenylacetic Acid in Arabidopsis

2019 ◽  
Vol 61 (3) ◽  
pp. 596-605 ◽  
Author(s):  
Yuki Aoi ◽  
Keita Tanaka ◽  
Sam David Cook ◽  
Ken-Ichiro Hayashi ◽  
Hiroyuki Kasahara
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Growth And Development ◽  
Phenylacetic Acid ◽  
Wild Type ◽  
Plant Growth And Development ◽  
Polar Movement ◽  
Wide Range ◽  
Metabolite Quantification ◽  
Indole 3 Acetic Acid

Abstract Auxin is the first discovered plant hormone and is essential for many aspects of plant growth and development. Indole-3-acetic acid (IAA) is the main auxin and plays pivotal roles in intercellular communication through polar auxin transport. Phenylacetic acid (PAA) is another natural auxin that does not show polar movement. Although a wide range of species have been shown to produce PAA, its biosynthesis, inactivation and physiological significance in plants are largely unknown. In this study, we demonstrate that overexpression of the CYP79A2 gene, which is involved in benzylglucosinolate synthesis, remarkably increased the levels of PAA and enhanced lateral root formation in Arabidopsis. This coincided with a significant reduction in the levels of IAA. The results from auxin metabolite quantification suggest that the PAA-dependent induction of GRETCHEN HAGEN 3 (GH3) genes, which encode auxin-amido synthetases, promote the inactivation of IAA. Similarly, an increase in IAA synthesis, via the indole-3-acetaldoxime pathway, significantly reduced the levels of PAA. The same adjustment of IAA and PAA levels was also observed by applying each auxin to wild-type plants. These results show that GH3 auxin-amido synthetases can alter the ratio of IAA and PAA in plant growth and development.

scholarly journals Synthetic promoter design in Escherichia coli based on a deep generative network

2020 ◽  
Vol 48 (12) ◽  
pp. 6403-6412 ◽  
Author(s):  
Ye Wang ◽  
Haochen Wang ◽  
Lei Wei ◽  
Shuailin Li ◽  
Liyang Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Predictive Model ◽  
De Novo ◽  
Sequence Similarity ◽  
Small Subset ◽  
Vast Number ◽  
Significant Sequence Similarity ◽  
E Coli ◽  
Synthetic Promoters ◽  
Naturally Occurring

Abstract Promoter design remains one of the most important considerations in metabolic engineering and synthetic biology applications. Theoretically, there are 450 possible sequences for a 50-nt promoter, of which naturally occurring promoters make up only a small subset. To explore the vast number of potential sequences, we report a novel AI-based framework for de novo promoter design in Escherichia coli. The model, which was guided by sequence features learned from natural promoters, could capture interactions between nucleotides at different positions and design novel synthetic promoters in silico. We combined a deep generative model that guides the search for artificial sequences with a predictive model to preselect the most promising promoters. The AI-designed promoters were optimized based on the promoter activity in E. coli and the predictive model. After two rounds of optimization, up to 70.8% of the AI-designed promoters were experimentally demonstrated to be functional, and few of them shared significant sequence similarity with the E. coli genome. Our work provided an end-to-end approach to the de novo design of novel promoter elements, indicating the potential to apply deep learning methods to de novo genetic element design.

scholarly journals Underground metabolism facilitates the evolution of novel pathways for vitamin B6 biosynthesis

2021 ◽  
Author(s):  
Björn Richts ◽  
Fabian M. Commichau
Keyword(s):  
Vitamin B6 ◽  
De Novo ◽  
Genetically Engineered ◽  
Biosynthetic Pathways ◽  
Genomic Plasticity ◽  
E Coli ◽  
Naturally Occurring ◽  
Genetic Lesion ◽  
Starting Point ◽  
Key Points

Abstract The term vitamin B6 is a designation for the vitamers pyridoxal, pyridoxamine, pyridoxine and the respective phosphate esters pyridoxal-5′-phosphate (PLP), pyridoxamine-5′-phosphate and pyridoxine-5′-phosphate. Animals and humans are unable to synthesise vitamin B6. These organisms have to take up vitamin B6 with their diet. Therefore, vitamin B6 is of commercial interest as a food additive and for applications in the pharmaceutical industry. As yet, two naturally occurring routes for de novo synthesis of PLP are known. Both routes have been genetically engineered to obtain bacteria overproducing vitamin B6. Still, major genetic engineering efforts using the existing pathways are required for developing fermentation processes that could outcompete the chemical synthesis of vitamin B6. Recent suppressor screens using mutants of the Gram-negative and Gram-positive model bacteria Escherichia coli and Bacillus subtilis, respectively, carrying mutations in the native pathways or heterologous genes uncovered novel routes for PLP biosynthesis. These pathways consist of promiscuous enzymes and enzymes that are already involved in vitamin B6 biosynthesis. Thus, E. coli and B. subtilis contain multiple promiscuous enzymes causing a so-called underground metabolism allowing the bacteria to bypass disrupted vitamin B6 biosynthetic pathways. The suppressor screens also show the genomic plasticity of the bacteria to suppress a genetic lesion. We discuss the potential of the serendipitous pathways to serve as a starting point for the development of bacteria overproducing vitamin B6. Key points • Known vitamin B6 routes have been genetically engineered. • Underground metabolism facilitates the emergence of novel vitamin B6 biosynthetic pathways. • These pathways may be suitable to engineer bacteria overproducing vitamin B6.

scholarly journals Redefining the roles of UDP-glycosyltransferases in auxin metabolism and homeostasis during plant development

2021 ◽  
Author(s):  
Eduardo Mateo-Bonmatí ◽  
Rubén Casanova-Sáez ◽  
Jan Šimura ◽  
Karin Ljung
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Plant Development ◽  
Plant Growth Regulator ◽  
Growth And Development ◽  
Plant Tissues ◽  
Plant Growth And Development ◽  
Concentration Gradients ◽  
Indole 3 Acetic Acid ◽  
Reversible Nature

ABSTRACTThe levels of the important plant growth regulator indole-3-acetic acid (IAA) are tightly controlled within plant tissues to spatiotemporally orchestrate concentration gradients that drive plant growth and development. Metabolic inactivation of bioactive IAA is known to participate in the modulation of IAA maxima and minima. IAA can be irreversibly inactivated by oxidation and conjugation to Aspartate and Glutamate. Usually overlooked because its reversible nature, the most abundant inactive IAA form is the IAA-glucose (IAA-glc) conjugate. Glycosylation of IAA is reported to be carried out by the UDP-glycosyltransferase 84B1 (UGT84B1), while UGT74D1 has been implicated in the glycosylation of the irreversibly formed IAA catabolite oxIAA. Here we demonstrate that both UGT84B1 and UGT74D1 modulate IAA levels throughout plant development by dual IAA and oxIAA glycosylation. Moreover, we identify a novel UGT subfamily whose members modulate IAA homeostasis during skotomorphogenesis by redundantly mediating the glycosylation of oxIAA.

scholarly journals Corynebacterium glutamicum Contains 3-Deoxy-d-Arabino-Heptulosonate 7-Phosphate Synthases That Display Novel Biochemical Features

2008 ◽  
Vol 74 (17) ◽  
pp. 5497-5503 ◽  
Author(s):  
Ya-Jun Liu ◽  
Pan-Pan Li ◽  
Ke-Xin Zhao ◽  
Bao-Jun Wang ◽  
Cheng-Ying Jiang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Corynebacterium Glutamicum ◽  
Feedback Inhibition ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Cloning And Expression ◽  
Dahp Synthase ◽  
E Coli ◽  
Phenotypic Alteration ◽  
In The Wild

ABSTRACT 3-Deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase (EC 2.5.1.54) catalyzes the first step of the shikimate pathway that finally leads to the biosynthesis of aromatic amino acids phenylalanine (Phe), tryptophan (Trp), and tyrosine (Tyr). In Corynebacterium glutamicum ATCC 13032, two chromosomal genes, NCgl0950 (aroF) and NCgl2098 (aroG), were located that encode two putative DAHP synthases. The deletion of NCgl2098 resulted in the loss of the ability of C. glutamicum RES167 (a restriction-deficient strain derived from C. glutamicum ATCC 13032) to grow in mineral medium; however, the deletion of NCgl0950 did not result in any observable phenotypic alteration. Analysis of DAHP synthase activities in the wild type and mutants of C. glutamicum RES167 indicated that NCgl2098, rather than NCgl0950, was involved in the biosynthesis of aromatic amino acids. Cloning and expression in Escherichia coli showed that both NCgl0950 and NCgl2098 encoded active DAHP synthases. Both the NCgl0950 and NCgl2098 DAHP synthases were purified from recombinant E. coli cells and characterized. The NCgl0950 DAHP synthase was sensitive to feedback inhibition by Tyr and, to a much lesser extent, by Phe and Trp. The NCgl2098 DAHP synthase was slightly sensitive to feedback inhibition by Trp, but not sensitive to Tyr and Phe, findings that were in contrast to the properties of previously known DAHP synthases from C. glutamicum subsp. flavum. Both Co2+ and Mn2+ significantly stimulated the NCgl0950 DAHP synthase's activity, whereas Mn2+ was much more stimulatory than Co2+ to the NCgl2098 DAHP synthase's activity.

The Biosynthesis of Phenylacetic Acids in the Blue-Green Alga Anacystis nidulans: Evidence for the Involvement of a Thylakoid-Bound ʟ-Amino Acid Oxidase

1977 ◽  
Vol 32 (5-6) ◽  
pp. 345-350 ◽  
Author(s):  
W. Löffelhardt
Keyword(s):  
Amino Acid ◽  
Phenylacetic Acid ◽  
Higher Plants ◽  
Aromatic Amino Acids ◽  
Anacystis Nidulans ◽  
Acid Oxidase ◽  
Reaction Sequence ◽  
Amino Acid Oxidase ◽  
Blue Green Algae ◽  
Hydroxyphenylacetic Acid

Abstract Phenylacetic acid and p-hydroxyphenylacetic acid are formed upon incubation of photosynthetic membranes from the prokaryotic alga Anacystis nidulans with ʟ-phenylalanine and ʟ-tyrosine, respectively. The corresponding phenylpyruvic acids act as intermediates as shown by trapping them as the stable oximino acids. The first step in this reaction sequence appears to be catalyzed by a thylakoid-bound ʟ-amino acid oxidase. Already existing evidence concerning phenylacetic acid formation at thylakoid membranes of higher plants via an ʟ-amino acid oxidase and the results obtained with A. nidulans give another example of aromatic amino acids between chloroplasts and blue-green algae.

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