scholarly journals The soluble Y115E–Y117E variant of human glutaminyl cyclase is a valid target for X-ray and NMR screening of inhibitors against Alzheimer disease

Author(s):  
Flavio DiPisa ◽  
Cecilia Pozzi ◽  
Manuela Benvenuti ◽  
Matteo Andreini ◽  
Guido Marconi ◽  
...  

Recent developments in molecular pathology and genetics have allowed the identification of human glutaminyl cyclase (hQC) among the abnormal proteins involved in many neurodegenerative disorders. Difficulties in obtaining large quantities of pure protein may limit the use of crystallographic screening for drug development on this target. Site-directed mutagenesis experiments have led to the identification of some solvent-exposed residues that are absolutely critical to achieve increased solubility and to avoid precipitation of the enzyme in inclusion bodies when expressed inEscherichia coli. The designed variant Y115E–Y117E has been found to be able to provide large amounts of monodisperse, pure hQC from anE. coliexpression system. To validate the use of the artificial construct as a target for large-scale X-ray and NMR screening campaigns in the search for new inhibitors of hQC, the X-ray crystal structures of the hQC Y115E–Y117E variant and of its adduct with the inhibitor PBD-150 were determined.

2014 ◽  
Vol 408 ◽  
pp. 35-45 ◽  
Author(s):  
Diego Moricoli ◽  
William Anthony Muller ◽  
Damiano Cosimo Carbonella ◽  
Maria Cristina Balducci ◽  
Sabrina Dominici ◽  
...  

Author(s):  
F. A. Durum ◽  
R. G. Goldman ◽  
T. J. Bolling ◽  
M. F. Miller

CMP-KDO synthetase (CKS) is an enzyme which plays a key role in the synthesis of LPS, an outer membrane component unique to gram negative bacteria. CKS activates KDO to CMP-KDO for incorporation into LPS. The enzyme is normally present in low concentrations (0.02% of total cell protein) which makes it difficult to perform large scale isolation and purification. Recently, the gene for CKS from E. coli was cloned and various recombinant DNA constructs overproducing CKS several thousandfold (unpublished data) were derived. Interestingly, no cytoplasmic inclusions of overproduced CKS were observed by EM (Fig. 1) which is in contrast to other reports of large proteinaceous inclusion bodies in various overproducing recombinant strains. The present immunocytochemical study was undertaken to localize CKS in these cells.Immune labeling conditions were first optimized using a previously described cell-free test system. Briefly, this involves soaking small blocks of polymerized bovine serum albumin in purified CKS antigen and subjecting them to various fixation, embedding and immunochemical conditions.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5538
Author(s):  
Zhongxuan Li ◽  
Qiang Cheng ◽  
Henan Guo ◽  
Rijun Zhang ◽  
Dayong Si

EF-1 is a novel peptide derived from two bacteriocins, plantaricin E and plantaricin F. It has a strong antibacterial activity against Escherichia coli and with negligible hemolytic effect on red blood cells. However, the chemical synthesis of EF-1 is limited by its high cost. In this study, we established a heterologous expression of EF-1 in Pichia pastoris. The transgenic strain successfully expressed hybrid EF-1 peptide, which had a molecular weight of ~5 kDa as expected. The recombinant EF-1 was purified by Ni2+ affinity chromatography and reversed-phase high performance liquid chromatography (RP-HPLC), which achieved a yield of 32.65 mg/L with a purity of 94.9%. The purified EF-1 exhibited strong antimicrobial and bactericidal activities against both Gram-positive and -negative bacteria. Furthermore, propidium iodide staining and scanning electron microscopy revealed that EF-1 can directly induce cell membrane permeabilization of E. coli. Therefore, the hybrid EF-1 not only preserves the individual properties of the parent peptides, but also acquires the ability to disrupt Gram-negative bacterial membrane. Meanwhile, such an expression system can reduce both the time and cost for large-scale peptide production, which ensures its potential application at the industrial level.


2005 ◽  
Vol 386 (4) ◽  
pp. 383-389 ◽  
Author(s):  
Simone Di Gennaro ◽  
Anna G. Ficca ◽  
Daniela Panichi ◽  
Elia Poerio

Abstract A cDNA encoding the proteinase inhibitor WSCI (wheat subtilisin/chymotrypsin inhibitor) was isolated by RT-PCR. Degenerate oligonucleotide primers were designed based on the amino acid sequence of WSCI and on the nucleotide sequence of the two homologous inhibitors (CI-2A and CI-2B) isolated from barley. For large-scale production, wsci cDNA was cloned into the E. coli vector pGEX-2T. The fusion protein GST-WSCI was efficiently produced in the bacterial expression system and, as the native inhibitor, was capable of inhibiting bacterial subtilisin, mammalian chymotrypsins and chymotrypsin-like activities present in crude extracts of a number of insect larvae (Helicoverpa armigera, Plodia interpunctella and Tenebrio molitor). The recombinant protein produced was also able to interfere with chymotrypsin-like activity isolated from immature wheat caryopses. These findings support a physiological role for this inhibitor during grain maturation.


2020 ◽  
Author(s):  
Jing Wang ◽  
Sheng Xu ◽  
Yang Pang ◽  
Xin Wang ◽  
Kequan Chen ◽  
...  

Abstract Background Currently, Streptomyces is widely used in the preparation of phospholipase D (PLD) with high transphosphatidylation activity. However, the yield of PLD from Streptomyces was low and the culture period was long. Therefore, an efficient and cost-effective method is needed urgently.Results Firstly, PLDs from Streptomyces PMF and Streptomyces racemochromogenes were separately over-expressed in E. coli to compare their transphosphatidylation activity based on the synthesis of phosphatidylserine (PS), and PLDPMF was determined to have higher activity. To further improve PLDPMF synthesis, a secretory expression system suitable for PLDPMF was constructed and optimized with different signal peptides. The highest secretory efficiency was observed when the PLDPMF gene was expressed together with its native signal peptide (Nat) and the signal peptide PelB from E. coli. For the application of recombinant PLD to PS synthesis, the PLD properties were characterized and 30.2 g/L of PS was produced after 24 h of bioconversion when 50 g/L phosphatidylcholine (PC) was added.Conclusions We succeeded in over-expressing PLD from Streptomyces PMF in E. coli with high transphosphatidylation activity and enhanced the yield by secretory expression. The secreted PLD was successfully used in the production of PS. Our work makes the large-scale production of PLD and PS feasible.


2019 ◽  
Author(s):  
Sorush Niknamian

Obesity is the prime suspect in a wide frequency of diabetes type II and cardiovascular diseases worldwide. Recombinant YY (tyrosine-tyrosine) peptide is a locally acting hormone, controlling secretion in the digestive tract. Interestingly, it was later shown that a truncated version of YY peptide, YY(3-36) peptide, has the potential as an important biopharmaceutical in a fight against obesity. This peptide has shown promising results in human clinical experiments in appetite reduction in human experiments. To develop an economical expression system for large-scale production of the peptide in gram-negative bacteria, we have developed a chimeric gene for extracellular expression of this peptide with the assistance of signal sequence of asparaginase II from Escherichia coli. This system has the advantage of producing the complete sequence of YY(3-36) without any extra tags that require further removal with the assistance of expensive specific proteases and reduce the downstream steps significantly. Our results pave the way for the recombinant production of YY(3-36) peptide and further proves the efficacy of asparaginase II signal sequence as a communicator of foreign peptides and proteins into extracellular space of E. coli.


Author(s):  
Amir Hossein Momen ◽  
Naser Harzandi ◽  
Azam Haddadi ◽  
Bijan Bambai

Abstract Background Increasing the expression rate of recombinant mammalian hormones in Escherichia coli by combining efficient promoters and signal sequences is a never ending process. A self-induced promoter will have some beneficial gains compared to the classical T7 promoter or its variants with isopropyl β-D-1-thiogalactopyranoside (IPTG) as the inducer. Obesity is the prime suspect in widespread frequency of diabetes type II and cardiovascular diseases worldwide. YY (tyrosine-tyrosine) peptide is a local acting hormone, controlling appetite. Excitingly, it was has been shown that a truncated version of the YY peptide, YY(3-36) peptide, has potential as a worthy biopharmaceutical agent in the fight against obesity. Materials and methods To develop an economical expression system for the large scale production of the peptide in Gram-negative bacteria, we introduced a promoter sequence upstream of a chimeric gene for the extracellular expression of this peptide with the assistance of a signal sequence of asparaginase II from E. coli. This system has the advantage of producing a complete sequence of a truncated YY peptide, YY(3-36), without any extra tags that would require further removal with the assistance of expensive specific proteases and reduced the downstream steps, significantly. Results Recombinant production of YY(3-36) peptide under a self-induced promoter proves the efficacy of the asparaginase II signal sequence as a communicator of foreign peptides and proteins into the extracellular space of E. coli. Conclusions The application of fusion protein expression of biopharmaceuticals, especially mammalian hormones, in prokaryotic systems with the help of native signal sequences makes some common tags with expensive proteases for the removal of the attached protein Tag redundant.


2004 ◽  
Vol 70 (6) ◽  
pp. 3292-3297 ◽  
Author(s):  
Gerard M. Gibbs ◽  
Barrie E. Davidson ◽  
Alan J. Hillier

ABSTRACT Piscicolin 126 is a class IIa bacteriocin isolated from Carnobacterium piscicola JG126 that exhibits strong activity against Listeria monocytogenes. The gene encoding mature piscicolin 126 (m-pisA) was cloned into an Escherichia coli expression system and expressed as a thioredoxin-piscicolin 126 fusion protein that was purified by affinity chromatography. Purified recombinant piscicolin 126 was obtained after CNBr cleavage of the fusion protein followed by reversed-phase chromatography. Recombinant piscicolin 126 contained a single disulfide bond and had a mass identical to that of native piscicolin 126. This novel bacteriocin expression system generated approximately 26 mg of purified bacteriocin from 1 liter of E. coli culture. The purified recombinant piscicolin 126 acted by disruption of the bacterial cell membrane.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Sy Le Thanh Nguyen ◽  
Dinh Thi Quyen ◽  
Hong Diep Vu

The streptokinase (SK) is emerging as an important thrombolytic therapy agent in the treatment of patients suffering from cardiovascular diseases. We reported highly effective renaturation of a SK fromS. pyogenessDT7 overexpressed inE. coli, purification, and biochemical characterization. A gene coding for the SK was cloned fromS. pyogenessDT7. Because accumulation of active SK is toxic to the host cells, we have expressed it in the form of inclusion bodies. The mature protein was overexpressed inE. coliBL21 DE3/pESK under the control of the strong promotertacinduced by IPTG with a level of 60% of the total cell proteins. The activity of the rSK, renatured in phosphate buffer supplemented with Triton X-100 and glycerol, was covered with up to 41 folds of its initial activity. The purified of protein was identified with MALDI-TOF mass spectrometry through four peptide fragments, which showed 100% identification to the corresponding peptides of the putative SK from GenBank. Due to overexpression and highly effective renaturation of large amounts of inclusion bodies, the recombinantE. coliBL21 DE3/pESK system could be potentially applied for large-scale production of SK used in the therapy of acute myocardial infarction.


1993 ◽  
Vol 294 (1) ◽  
pp. 293-299 ◽  
Author(s):  
G Fiermonte ◽  
J E Walker ◽  
F Palmieri

The oxoglutarate carrier, an intrinsic membrane-transport protein of the inner membranes of bovine-heart mitochondria, has been expressed at an abundant level in Escherichia coli. It accumulates in the bacterium as inclusion bodies, and none of the protein was detected in the bacterial inner membrane. The mitochondrial ADP/ATP carrier, a member of the same super-family of transport proteins as the oxoglutarate carrier, has also been expressed in E. coli. However, the expression of the ADP/ATP carrier in bacteria retards their growth, and so the levels of expression that were attained were lower than those of the oxoglutarate carrier. The oxoglutarate carrier inclusion bodies have been disaggregated with the detergent N-dodecanoyl-sarcosine, and the protein has been incorporated into liposomes. In its ability to transport oxoglutarate and malate and other known substrates of the carrier in mitochondria, and in its inhibition characteristics by a wide range of non-competitive and competitive inhibitors, this reconstituted oxoglutarate carrier is similar to the natural protein in the inner membranes of mitochondria, and to the carrier that has been purified from mitochondria and reconstituted in liposomes. These experiments remove significant obstacles to crystallization trials and to site-directed mutagenesis of the oxoglutarate carrier.


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