scholarly journals Recombinant and endogenous ways to produce methylated phospholipids in Escherichia coli

2021 ◽  
Author(s):  
Julia Kleetz ◽  
Georgios Vasilopoulos ◽  
Simon Czolkoss ◽  
Meriyem Aktas ◽  
Franz Narberhaus
Keyword(s):  
Escherichia Coli ◽  
Acyl Carrier Protein ◽  
Ectopic Expression ◽  
Regular Component ◽  
Membrane Composition ◽  
Protein Biochemistry ◽  
E Coli ◽  
Expression Of Genes ◽  
Versatile Tool ◽  
Endogenous Proteins

AbstractEscherichia coli is the daily workhorse in molecular biology research labs and an important platform microorganism in white biotechnology. Its cytoplasmic membrane is primarily composed of the phospholipids phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CL). As in most other bacteria, the typical eukaryotic phosphatidylcholine (PC) is not a regular component of the E. coli membrane. PC is known to act as a substrate in various metabolic or catabolic reactions, to affect protein folding and membrane insertion, and to activate proteins that originate from eukaryotic environments. Options to manipulate the E. coli membrane to include non-native lipids such as PC might make it an even more powerful and versatile tool for biotechnology and protein biochemistry. This article outlines different strategies how E. coli can be engineered to produce PC and other methylated PE derivatives. Several of these approaches rely on the ectopic expression of genes from natural PC-producing organisms. These include PC synthases, lysolipid acyltransferases, and several phospholipid N-methyltransferases with diverse substrate and product preferences. In addition, we show that E. coli has the capacity to produce PC by its own enzyme repertoire provided that appropriate precursors are supplied. Screening of the E. coli Keio knockout collection revealed the lysophospholipid transporter LplT to be responsible for the uptake of lyso-PC, which is then further acylated to PC by the acyltransferase-acyl carrier protein synthetase Aas. Overall, our study shows that the membrane composition of the most routinely used model bacterium can readily be tailored on demand.Key points• Escherichia coli can be engineered to produce non-native methylated PE derivatives.• These lipids can be produced by foreign and endogenous proteins.• Modification of E. coli membrane offers potential for biotechnology and research. Graphical abstract

scholarly journals Spontaneous Cleavages of a Heterologous Protein, the CenA Endoglucanase of Cellulomonas fimi, in Escherichia coli

2021 ◽  
Vol 14 ◽  
pp. 117863612110246
Author(s):  
Cheuk Yin Lai ◽  
Ka Lun Ng ◽  
Hao Wang ◽  
Chui Chi Lam ◽  
Wan Keung Raymond Wong
Keyword(s):  
Escherichia Coli ◽  
Cellulolytic Bacterium ◽  
Systematic Screening ◽  
Cellulomonas Fimi ◽  
E Coli ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Glycosylation Sites ◽  
Endogenous Proteins ◽  
Cellulose Binding

CenA is an endoglucanase secreted by the Gram-positive cellulolytic bacterium, Cellulomonas fimi, to the environment as a glycosylated protein. The role of glycosylation in CenA is unclear. However, it seems not crucial for functional activity and secretion since the unglycosylated counterpart, recombinant CenA (rCenA), is both bioactive and secretable in Escherichia coli. Using a systematic screening approach, we have demonstrated that rCenA is subjected to spontaneous cleavages (SC) in both the cytoplasm and culture medium of E. coli, under the influence of different environmental factors. The cleavages were found to occur in both the cellulose-binding (CellBD) and catalytic domains, with a notably higher occurring rate detected in the former than the latter. In CellBD, the cleavages were shown to occur close to potential N-linked glycosylation sites, suggesting that these sites might serve as ‘attributive tags’ for differentiating rCenA from endogenous proteins and the points of initiation of SC. It is hypothesized that glycosylation plays a crucial role in protecting CenA from SC when interacting with cellulose in the environment. Subsequent to hydrolysis, SC would ensure the dissociation of CenA from the enzyme-substrate complex. Thus, our findings may help elucidate the mechanisms of protein turnover and enzymatic cellulolysis.

scholarly journals Activation of Toxin-Antitoxin System Toxins Suppresses Lethality Caused by the Loss of σEin Escherichia coli

2015 ◽  
Vol 197 (14) ◽  
pp. 2316-2324 ◽  
Author(s):  
Yasushi Daimon ◽  
Shin-ichiro Narita ◽  
Yoshinori Akiyama
Keyword(s):  
Escherichia Coli ◽  
Stress Responses ◽  
Ectopic Expression ◽  
Growth Media ◽  
Content Type ◽  
E Coli ◽  
Envelope Stress ◽  
Genes Encoding ◽  
Σ Factor ◽  
Mutant Forms

ABSTRACTσE, an alternative σ factor that governs a major signaling pathway in envelope stress responses in Gram-negative bacteria, is essential for growth ofEscherichia colinot only under stressful conditions, such as elevated temperature, but also under normal laboratory conditions. A mutational inactivation of thehicBgene has been reported to suppress the lethality caused by the loss of σE.hicBencodes the antitoxin of the HicA-HicB toxin-antitoxin (TA) system; overexpression of the HicA toxin, which exhibits mRNA interferase activity, causes cleavage of mRNAs and an arrest of cell growth, while simultaneous expression of HicB neutralizes the toxic effects of overproduced HicA. To date, however, how the loss of HicB rescues the cell lethality in the absence of σEand, more specifically, whether HicA is involved in this process remain unknown. Here we showed that simultaneous disruption ofhicAabolished suppression of the σEessentiality in the absence ofhicB, while ectopic expression of wild-type HicA, but not that of its mutant forms without mRNA interferase activity, restored the suppression. Furthermore, HicA and two other mRNA interferase toxins, HigB and YafQ, suppressed the σEessentiality even in the presence of chromosomally encoded cognate antitoxins when these toxins were overexpressed individually. Interestingly, when the growth media were supplemented with low levels of antibiotics that are known to activate toxins,E. colicells with no suppressor mutations grew independently of σE. Taken together, our results indicate that the activation of TA system toxins can suppress the σEessentiality and affect the extracytoplasmic stress responses.IMPORTANCEσEis an alternative σ factor involved in extracytoplasmic stress responses. Unlike other alternative σ factors, σEis indispensable for the survival ofE. colieven under unstressed conditions, although the exact reason for its essentiality remains unknown. Toxin-antitoxin (TA) systems are widely distributed in prokaryotes and are composed of two adjacent genes, encoding a toxin that exerts harmful effects on the toxin-producing bacterium itself and an antitoxin that neutralizes the cognate toxin. Curiously, it is known that inactivation of an antitoxin rescues the σEessentiality, suggesting a connection between TA systems and σEfunction. We demonstrate here that toxin activation is necessary for this rescue and suggest the possible involvement of TA systems in extracytoplasmic stress responses.

scholarly journals Purification and separation of holo- and apo-forms of Saccharopolyspora erythraea acyl-carrier protein released from recombinant Escherichia coli by freezing and thawing

1993 ◽  
Vol 294 (2) ◽  
pp. 521-527 ◽  
Author(s):  
S A Morris ◽  
W P Revill ◽  
J Staunton ◽  
P F Leadlay
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Acyl Carrier Protein ◽  
Saccharopolyspora Erythraea ◽  
Carrier Protein ◽  
Freezing And Thawing ◽  
Acyl Carrier Proteins ◽  
Expression Plasmid ◽  
E Coli ◽  
Protein Dimer

Saccharopolyspora erythraea acyl-carrier protein, highly expressed from a T7-based expression plasmid in Escherichia coli, can be selectively released from the cells in near-quantitative yield by a single cycle of freezing and thawing in a neutral buffer. Electrospray mass spectrometry was used to confirm that the recombinant S. erythraea acyl-carrier protein over-expressed in E. coli is present predominantly as the holo-form, with variable amounts of apo-acyl-carrier protein, holo-acyl-carrier protein dimer and holo-acyl-carrier protein glutathione adduct. The holo- and apo-acyl-carrier proteins are both readily purified on a large scale from the freeze-thaw extracts and can be separated from one another by octyl-Sepharose chromatography. The holo-acyl-carrier protein obtained in this way was fully active in supporting the synthesis of acyl-acyl-carrier protein by extracts of S. erythraea.

scholarly journals Improved Squalene Production via Modulation of the Methylerythritol 4-Phosphate Pathway and Heterologous Expression of Genes from Streptomyces peucetius ATCC 27952 in Escherichia coli

2009 ◽  
Vol 75 (22) ◽  
pp. 7291-7293 ◽  
Author(s):  
Gopal Prasad Ghimire ◽  
Hei Chan Lee ◽  
Jae Kyung Sohng
Keyword(s):  
Escherichia Coli ◽  
Heterologous Expression ◽  
Farnesyl Diphosphate ◽  
Farnesyl Diphosphate Synthase ◽  
Isopentenyl Diphosphate ◽  
Isopentenyl Diphosphate Isomerase ◽  
Streptomyces Peucetius ◽  
E Coli ◽  
Expression Of Genes ◽  
Genes Encoding

ABSTRACT Putative hopanoid genes from Streptomyces peucetius were introduced into Escherichia coli to improve the production of squalene, an industrially important compound. High expression of hopA and hopB (encoding squalene/phytoene synthases) together with hopD (encoding farnesyl diphosphate synthase) yielded 4.1 mg/liter of squalene. This level was elevated to 11.8 mg/liter when there was also increased expression of dxs and idi, E. coli genes encoding 1-deoxy-d-xylulose 5-phosphate synthase and isopentenyl diphosphate isomerase.

scholarly journals Conversion of Norepinephrine to 3,4-Dihdroxymandelic Acid in Escherichia coli Requires the QseBC Quorum-Sensing System and the FeaR Transcription Factor

2017 ◽  
Vol 200 (1) ◽  
Author(s):  
Sasikiran Pasupuleti ◽  
Nitesh Sule ◽  
Michael D. Manson ◽  
Arul Jayaraman
Keyword(s):  
Escherichia Coli ◽  
Transcription Factor ◽  
Quorum Sensing ◽  
Aromatic Amines ◽  
Response Regulator ◽  
Content Type ◽  
E Coli ◽  
Expression Of Genes ◽  
K 12 ◽  
Cognate Response Regulator

ABSTRACTThe detection of norepinephrine (NE) as a chemoattractant byEscherichia colistrain K-12 requires the combined action of the TynA monoamine oxidase and the FeaB aromatic aldehyde dehydrogenase. The role of these enzymes is to convert NE into 3,4-dihydroxymandelic acid (DHMA), which is a potent chemoattractant sensed by the Tsr chemoreceptor. These two enzymes must be induced by prior exposure to NE, and cells that are exposed to NE for the first time initially show minimal chemotaxis toward it. The induction of TynA and FeaB requires the QseC quorum-sensing histidine kinase, and the signaling cascade requires new protein synthesis. Here, we demonstrate that the cognate response regulator for QseC, the transcription factor QseB, is also required for induction. The related quorum-sensing kinase QseE appears not to be part of the signaling pathway, but its cognate response regulator, QseF, which is also a substrate for phosphotransfer from QseC, plays a nonessential role. The promoter of thefeaRgene, which encodes a transcription factor that has been shown to be essential for the expression oftynAandfeaB, has two predicted QseB-binding sites. One of these sites appears to be in an appropriate position to stimulate transcription from the P1promoter of thefeaRgene. This study unites two well-known pathways: one for expression of genes regulated by catecholamines (QseBC) and one for expression of genes required for metabolism of aromatic amines (FeaR, TynA, and FeaB). This cross talk allowsE. colito convert the host-derived and chemotactically inert NE into the potent bacterial chemoattractant DHMA.IMPORTANCEThe chemotaxis ofE. coliK-12 to norepinephrine (NE) requires the conversion of NE to 3,4-dihydroxymandleic acid (DHMA), and DHMA is both an attractant and inducer of virulence gene expression for a pathogenic enterohemorrhagicE. coli(EHEC) strain. The induction of virulence by DHMA and NE requires QseC. The results described here show that the cognate response regulator for QseC, QseB, is also required for conversion of NE into DHMA. Production of DHMA requires induction of a pathway involved in the metabolism of aromatic amines. Thus, the QseBC sensory system provides a direct link between virulence and chemotaxis, suggesting that chemotaxis to host signaling molecules may require that those molecules are first metabolized by bacterial enzymes to generate the actual chemoattractant.

scholarly journals Regulation of RraA, a Protein Inhibitor of RNase E-Mediated RNA Decay

2006 ◽  
Vol 188 (9) ◽  
pp. 3257-3263 ◽  
Author(s):  
Meng Zhao ◽  
Li Zhou ◽  
Yasuaki Kawarasaki ◽  
George Georgiou
Keyword(s):  
Escherichia Coli ◽  
Intergenic Region ◽  
Ectopic Expression ◽  
Dependent Manner ◽  
Feedback Circuit ◽  
Rnase E ◽  
Protein Inhibitor ◽  
E Coli ◽  
The Stability ◽  
Fusion Analysis

ABSTRACT The recently discovered RraA protein acts as an inhibitor of the essential endoribonuclease RNase E, and we demonstrated that ectopic expression of RraA affects the abundance of more than 700 transcripts in Escherichia coli (K. Lee, X. Zhan, J. Gao, J. Qiu, Y. Feng, R. Meganathan, S. N. Cohen, and G. Georgiou, Cell 114:623-634, 2003). We show that rraA is expressed from its own promoter, P rraA , located in the menA-rraA intergenic region. Primer extension and lacZ fusion analysis revealed that transcription from P rraA is elevated upon entry into stationary phase in a σs-dependent manner. In addition, the stability of the rraA transcript is dependent on RNase E activity, suggesting the involvement of a feedback circuit in the regulation of the RraA level in E. coli.

scholarly journals From reporters to endogenous genes: the impact of the first five codons on translation efficiency in Escherichia coli

2019 ◽  
Author(s):  
Mariana H. Moreira ◽  
Géssica C. Barros ◽  
Rodrigo D. Requião ◽  
Silvana Rossetto ◽  
Tatiana Domitrovic ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Protein Expression ◽  
Nucleotide Composition ◽  
Control Mechanisms ◽  
Translation Efficiency ◽  
Coding Region ◽  
E Coli ◽  
Endogenous Proteins ◽  
The Impact

ABSTRACTTranslation initiation is a critical step in the regulation of protein synthesis, and it is subjected to different control mechanisms, such as 5’ UTR secondary structure and initiation codon context, that can influence the rates at which initiation and consequentially translation occur. For some genes, translation elongation also affects the rate of protein synthesis. With a GFP library containing nearly all possible combinations of nucleotides from the 3rd to the 5th codon positions in the protein coding region of the mRNA, it was previously demonstrated that some nucleotide combinations increased GFP expression up to four orders of magnitude. While it is clear that the codon region from positions 3 to 5 can influence protein expression levels of artificial constructs, its impact on endogenous proteins is still unknown. Through bioinformatics analysis, we identified the nucleotide combinations of the GFP library in Escherichia coli genes and examined the correlation between the expected levels of translation according to the GFP data with the experimental measures of protein expression. We observed that E. coli genes were enriched with the nucleotide compositions that enhanced protein expression in the GFP library, but surprisingly, it seemed to affect the translation efficiency only marginally. Nevertheless, our data indicate that different enterobacteria present similar nucleotide composition enrichment as E. coli, suggesting an evolutionary pressure towards the conservation of short translational enhancer sequences.

scholarly journals Purification and characterization of [acyl-carrier-protein] acetyltransferase from Escherichia coli

1988 ◽  
Vol 250 (3) ◽  
pp. 789-796 ◽  
Author(s):  
P N Lowe ◽  
S Rhodes
Keyword(s):  
Escherichia Coli ◽  
Acyl Carrier Protein ◽  
Carrier Protein ◽  
E Coli ◽  
Step Procedure ◽  
Ping Pong ◽  
Protein Acetyltransferase ◽  
Enzyme Intermediate ◽  
Specific Reagent

A multi-step procedure has been developed for the purification of [acyl-carrier-protein] acetyltransferase from Escherichia coli, which allows the production of small amounts of homogeneous enzyme. The subunit Mr was estimated to be 29,000 and the native Mr was estimated to be 61,000, suggesting a homodimeric structure. The catalytic properties of the enzyme are consistent with a Bi Bi Ping Pong mechanism and the existence of an acetyl-enzyme intermediate in the catalytic cycle. The enzyme was inhibited by N-ethylmaleimide and more slowly by iodoacetamide in reactions protected by the substrate, acetyl-CoA. However, the enzyme was apparently only weakly inhibited by the thiol-specific reagent methyl methanethiosulphonate. The nature of the acetyl-enzyme intermediate is discussed in relationship to that found in other similar enzymes from E. coli, yeast and vertebrates.

Effect of endotoxin on capillary permeability to macromolecules

1964 ◽  
Vol 207 (3) ◽  
pp. 518-522 ◽  
Author(s):  
S. Chien ◽  
D. G. Sinclair ◽  
R. J. Dellenback ◽  
C. Chang ◽  
B. Peric ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Intravenous Injection ◽  
Thoracic Duct ◽  
Capillary Permeability ◽  
Lymph Flow ◽  
Thoracic Duct Lymph ◽  
E Coli ◽  
Duct Lymph ◽  
Endogenous Proteins

The intravenous injection of Escherichia coli endotoxin (3 mg/kg) into dogs caused an increase in lymph flow from the thoracic duct. The lymph concentrations of macromolecules (dextran with mol. wt. of 250,000, albumin-I131, and endogenous proteins) increased and the lymph-to-plasma ratios approached 1. These results indicate that E. coli endotoxin causes an increase in capillary permeability to both the fluid and the macromolecules in plasma. The increase in capillary permeability for albumin-I131 was greater than that for dextran with mol. wt. of 250,000. Eighty minutes after endotoxin, the lymph flow returned to normal, but albumin-I131 and dextran injected at this time were still transferred into the thoracic duct lymph at enhanced rates.

scholarly journals Coexpression of Genetically Engineered 3-Ketoacyl-ACP Synthase III (fabH) and Polyhydroxyalkanoate Synthase (phaC) Genes Leads to Short-Chain-Length-Medium-Chain-Length Polyhydroxyalkanoate Copolymer Production from Glucose in Escherichia coli JM109

2004 ◽  
Vol 70 (2) ◽  
pp. 999-1007 ◽  
Author(s):  
Christopher T. Nomura ◽  
Kazunori Taguchi ◽  
Seiichi Taguchi ◽  
Yoshiharu Doi
Keyword(s):  
Escherichia Coli ◽  
Chain Length ◽  
Acyl Carrier Protein ◽  
Short Chain ◽  
Pha Synthase ◽  
Short Chain Length ◽  
E Coli ◽  
Medium Chain ◽  
Medium Chain Length ◽  
Pha Copolymers

ABSTRACT Polyhydroxyalkanoates (PHAs) can be divided into three main types based on the sizes of the monomers incorporated into the polymer. Short-chain-length (SCL) PHAs consist of monomer units of C3 to C5, medium-chain-length (MCL) PHAs consist of monomer units of C6 to C14, and SCL-MCL PHAs consist of monomers ranging in size from C4 to C14. Although previous studies using recombinant Escherichia coli have shown that either SCL or MCL PHA polymers could be produced from glucose, this study presents the first evidence that an SCL-MCL PHA copolymer can be made from glucose in recombinant E. coli. The 3-ketoacyl-acyl carrier protein synthase III gene (fabH) from E. coli was modified by saturation point mutagenesis at the codon encoding amino acid 87 of the FabH protein sequence, and the resulting plasmids were cotransformed with either the pAPAC plasmid, which harbors the Aeromonas caviae PHA synthase gene (phaC), or the pPPAC plasmid, which harbors the Pseudomonas sp. strain 61-3 PHA synthase gene (phaC1), and the abilities of these strains to accumulate PHA from glucose were assessed. It was found that overexpression of several of the mutant fabH genes enabled recombinant E. coli to induce the production of monomers of C4 to C10 and subsequently to produce unusual PHA copolymers containing SCL and MCL units. The results indicate that the composition of PHA copolymers may be controlled by the monomer-supplying enzyme and further reinforce the idea that fatty acid biosynthesis may be used to supply monomers for PHA production.

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