scholarly journals Identification, Cloning, and Expression of L-Amino Acid Oxidase from MarinePseudoalteromonassp. B3

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zhiliang Yu ◽  
Ning Zhou ◽  
Hua Qiao ◽  
Juanping Qiu

L-amino acid oxidase (LAAO) is attracting more attentions due to its broad and important biological functions. Recently, an LAAO-producing marine microorganism (strain B3) was isolated from the intertidal zone of Dinghai sea area, China. Physiological, biochemical, and molecular identifications together with phylogenetic analysis congruously suggested that it belonged to the genusPseudoalteromonas. Therefore, it was designated asPseudoalteromonassp. B3. Its capability of LAAO production was crossly confirmed by measuring the products of H2O2, a-keto acids, andNH4+in oxidization reaction. Two rounds of PCR were performed to gain the entire B3-LAAO gene sequence of 1608 bps in length encoding for 535 amino acid residues. This deduced amino acid sequence showed 60 kDa of the calculated molecular mass, supporting the SDS-PAGE result. Like most of flavoproteins, B3-LAAO also contained two conserved typical motifs, GG-motif andβαβ-dinucleotide-binding domain motif. On the other hand, its unique substrate spectra and sequence information suggested that B3-LAAO was a novel LAAO. Our results revealed that it could be functionally expressed inE. coliBL21(DE3) using vectors, pET28b(+) and pET20b(+). However, compared with the native LAAO, the expression level of the recombinant one was relatively low, most probably due to the formation of inclusion bodies. Several solutions are currently being conducted in our lab to increase its expression level.

2021 ◽  
Vol 11 (1) ◽  
pp. 21-29
Author(s):  
Ho Ta Giap ◽  
Phan Ngoc Han ◽  
Tran Le Duy Phuong ◽  
Phung Thi Thu Phung ◽  
Vu Van Van

Introduction: The level of serum HbA1c is an indicator of the average blood sugar level in the last three months. HbA1c can be quantified using assays involving the enzyme fructosyl amino acid oxidase (FAOX). This study aims to produce GST-tagged FAOX-TE (GST/FAOX-TE), a thermal stable and specific variant of FAOX, for future application studies. Materials and methods: The E. coli strains DH5α and BL21 (DE3) were used as cloning and expression hosts, respectively. The FAOX-TE sequence was synthesized at IDT (US) and clonned into pGEX-4T3 vector, which was confirmed by Colony PCR. The expression was induced at 16°C, 0.5 mM IPTG in LB media containing 50 µg/ml ampicilin. The protein expression profile was analyzed by SDS-PAGE. The cell pellet was sonicated and purified by Glutathione Sepharose 4 Fast Flow (Cytiva, US). The catalytic activity of GST/FAOX-TE with fructosyl valine was determined using high performance anion exchange chromatography with pulsed amperometry detection (HPAEC-PAD). Results: The fusion protein was successfully expressed in Escherichia coli using the plasmid pGEX-4T3 and purified to high purity 93%. Recombinant GST/FAOX-TE was shown to be active on fructosyl valine. Conclusions: Active GST/FAOX-TE was successfully expressed in E. coli BL21 (DE3) and purified, which will be used for future development of biosensors for fructosyl valine quantification.


2018 ◽  
Vol 54 (4A) ◽  
pp. 123
Author(s):  
Vu Thi Hanh

The synthesis of 7-ACA from cephalosporin C (CPC) by a two-step bioconversion using D-amino acid oxidase (DAAO) and glutaryl 7-ACA acylase (GLA) has been effectively and largely applied in pharmaceutical industry. In this study, the gene gla coding for 720-amino acid GLA from plasmid pUC57::gla was analyzed and successfully inserted into vector pET22b(+) to form expression vector pET22b(+)::gla. The newly constructed expression vector pET22b(+)::gla was cloned and then transformed into Escherichia coli BL21(DE3) to generate recombinant strain E. coli BL21(DE3)[pET22b(+)::gla]. The suitable conditions for expression of gla gene were in LB medium at 30 oC and induced by 0.4 mM of Isopropyl β-D-1-thiogalactopyranoside (IPTG) for 3 hours. Under the chosen culturing parameters, expression of gla gene by E. coli BL21(DE3)/[pET22b(+)::gla] resulted in a recombinant GLA (rGLA) with molecular weight of 83 kDa and catalytic activity of 2.7 U/mg of total protein. Experimental research on immobilization of rGLA onto ten nanoporous materials were showed that, SBA-15 was the best one for immobilization of rGLA, reaching activity of immobilized enzyme of 22.2 U/g matrix. Furthermore, optimal conditions of procedure for immobilizing rGLA on nanomaterials (SBA-15) were determined as follows: temperature is 25 °C, pH7.0 and immobilization time –60 minutes. Therefore the results reported in this study revealed the successfully heterologous expression of GLA in recombinant E. coli and potential immobilization of enzyme on inorganic nano-materials.


2019 ◽  
Vol 6 (4) ◽  
pp. 182035 ◽  
Author(s):  
Licheng Wu ◽  
Xiaolei Guo ◽  
Gaobing Wu ◽  
Pengfu Liu ◽  
Ziduo Liu

α-keto acids are compounds of primary interest for the fine chemical, pharmaceutical and agrochemical sectors. l -amino acid oxidases as an efficient tool are used for α-keto acids preparation in this study. Firstly, an l -amino acid oxidase ( Pmi LAAO) from Proteus mirabilis was discovered by data mining . Secondly, by gene expression vector screening, pETDuet-1- Pmi LAAO activity improved by 130%, as compared to the pET20b- Pmi LAAO. Pmi LAAO production was increased to 9.8 U ml −1 by optimized expression condition (OD 600 = 0.65, 0.45 mmol l −1 IPTG, 20 h of induction). Furthermore, The Pmi LAAO was stabile in the pH range of 4.0–9.0 and in the temperature range of 10–40°C; the optimal pH and temperature of recombinant Pmi LAAO were 6.5 and 37°C, respectively. Afterwards, in order to simplify product separation process, E. coli -pETduet-1- Pmi LAAO was immobilized in Ca-alginate beads. Continuous production of 2-oxo-3-phenylpropanoic acid was conducted in a packed-bed reactor via immobilized E. coli -pETduet-1- Pmi LAAO. Significantly, 29.66 g l −1 2-oxo-3-phenylpropanoic acid with a substrate conversion rate of 99.5% was achieved by correspondingly increasing the residence time (25 h). This method holds the potential to be used for efficiently producing pure α-keto acids.


2021 ◽  
Vol 24 (5) ◽  
pp. 161-169
Author(s):  
Enny Ratnaningsih ◽  
Lousiana Dwinta Utami ◽  
Nurlaida Nurlaida ◽  
Rindia Maharani Putri

Organohalogens are widely utilized as pesticides, herbicides, solvents, and for many other industrial purposes. However, the use of these compounds caused some negative impacts to the environment due to their toxicity and persistency. In the light of this, some microbes have been identified and employed to perform dehalogenation, converting halogenated organic compounds to non-toxic materials. In this research, we successfully cloned and sequenced the haloacid dehalogenase gene from a local Pseudomonas aeruginosa ITB1 strain, which is involved in the degradation of monochloroacetate. First, the haloacid dehalogenase gene was amplified by PCR using a pair of primers designed from the same gene sequences of other P. aeruginosa strains available in the GenBank. The cloned gene in pGEM-T in E. coli TOP10 was sequenced, analyzed, and then sub-cloned into pET-30a(+) for expression in E. coli BL21 (DE3). To facilitate direct sub-cloning, restriction sequences of EcoRI (G/AATTC) and HindIII (A/AGCTT) were added to the forward and reversed primers, respectively. The expressed protein in E. coli BL21 (DE3) appeared as a 26-kDa protein in SDS-PAGE analysis, which is in good agreement with the size predicted by ExPASy Protparam. We obtained that the best expression in LB liquid medium was achieved with 0.01 mM IPTG induction at 30°C incubation for 3 hours. We also found that the enzyme is more concentrated in the pellet cells as inclusion bodies. Furthermore, the in-silico analysis revealed that this enzyme consists of 233 amino acid residues. This enzyme’s predicted tertiary structure shows six β-sheets flanked by α-helixes and thus belongs to Group II haloacid dehalogenase. Based on the structural prediction, amino acid residues of Asp7, Ser121, and Asn122 are present in the active site and might play essential roles in catalysis. The presented study laid the foundation for recombinant haloacid dehalogenase production from P. aeruginosa local strains. It provided an insight into the utilization of recombinant local strains to remediate environmental problems caused by organohalogens.


Author(s):  
Giulia Murtas ◽  
Silvia Sacchi ◽  
Gabriella Tedeschi ◽  
Elisa Maffioli ◽  
Eugenio Notomista ◽  
...  

AbstractThe flavoenzyme d-amino acid oxidase (DAAO) is deputed to the degradation of d-enantiomers of amino acids. DAAO plays various relevant physiological roles in different organisms and tissues. Thus, it has been recently suggested that the goblet cells of the mucosal epithelia secrete into the lumen of intestine, a processed and active form of DAAO that uses the intestinal d-amino acids to generate hydrogen peroxide (H2O2), an immune messenger that helps fighting gut pathogens, and by doing so controls the homeostasis of gut microbiota. Here, we show that the DAAO form lacking the 1–16 amino acid residues (the putative secretion signal) is unstable and inactive, and that DAAO is present in the epithelial layer and the mucosa of mouse gut, where it is largely proteolyzed. In silico predicted DAAO-derived antimicrobial peptides show activity against various Gram-positive and Gram-negative bacteria but not on Lactobacilli species, which represent the commensal microbiota. Peptidomic analysis reveals the presence of such peptides in the mucosal fraction. Collectively, we identify a novel mechanism for gut microbiota selection implying DAAO-derived antimicrobial peptides which are generated by intestinal proteases and that are secreted in the gut lumen. In conclusion, we herein report an additional, ancillary role for mammalian DAAO, unrelated to its enzymatic activity.


1999 ◽  
Vol 65 (3) ◽  
pp. 910-915 ◽  
Author(s):  
Yoshinobu Terada ◽  
Kazutoshi Fujii ◽  
Takeshi Takaha ◽  
Shigetaka Okada

ABSTRACT The amylomaltase gene of the thermophilic bacterium Thermus aquaticus ATCC 33923 was cloned and sequenced. The open reading frame of this gene consisted of 1,503 nucleotides and encoded a polypeptide that was 500 amino acids long and had a calculated molecular mass of 57,221 Da. The deduced amino acid sequence of the amylomaltase exhibited a high level of homology with the amino acid sequence of potato disproportionating enzyme (D-enzyme) (41%) but a low level of homology with the amino acid sequence of theEscherichia coli amylomaltase (19%). The amylomaltase gene was overexpressed in E. coli, and the enzyme was purified. This enzyme exhibited maximum activity at 75°C in a 10-min reaction with maltotriose and was stable at temperatures up to 85°C. When the enzyme acted on amylose, it catalyzed an intramolecular transglycosylation (cyclization) reaction which produced cyclic α-1,4-glucan (cycloamylose), like potato D-enzyme. The yield of cycloamylose produced from synthetic amylose with an average molecular mass of 110 kDa was 84%. However, the minimum degree of polymerization (DP) of the cycloamylose produced by T. aquaticus enzyme was 22, whereas the minimum DP of the cycloamylose produced by potato D-enzyme was 17. The T. aquaticus enzyme also catalyzed intermolecular transglycosylation of maltooligosaccharides. A detailed analysis of the activity of T. aquaticus ATCC 33923 amylomaltase with maltooligosaccharides indicated that the catalytic properties of this enzyme differ from those of E. coliamylomaltase and the plant D-enzyme.


Gene ◽  
1990 ◽  
Vol 90 (2) ◽  
pp. 293-297 ◽  
Author(s):  
Masazumi Tada ◽  
Kiyoshi Fukui ◽  
Kyoko Momoi ◽  
Yoshimiro Miyake

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