scholarly journals Molecular cloning and expression in Escherichia coli of a gene coding for bovine S100A1 protein and its Glu32-->Gln and Glu73-->Gln mutants.

1997 ◽  
Vol 44 (2) ◽  
pp. 275-283 ◽  
Author(s):  
K Bolewska ◽  
H Kozłowska ◽  
G Goch ◽  
B Mikołajek ◽  
A Bierzyński
Keyword(s):  
Escherichia Coli ◽  
Calcium Binding ◽  
Expression System ◽  
Total Yield ◽  
Site Directed Mutagenesis ◽  
Cloning And Expression ◽  
Alpha Subunits ◽  
C Terminus ◽  
Gene Coding ◽  
Native Sequence

Calcium binding S100A1 protein consists of two S100 alpha subunits. On the basis of sequence homology to other S100 proteins it is believed that the binding loops are formed by amino-acid residues 19-32 and 62-73 of S100 alpha polypeptide chain. In the oxidized form of the protein the subunits are linked covalently with each other by a disulphide bond between their Cys85 residues. A synthetic gene coding for bovine S100 alpha subunit was constructed and cloned into a derivative of pAED4 plasmid. The gene was expressed in Escherichia coli utilizing the T7 expression system. The expression products were purified and identified using mass spectrometry and by sequencing of their N- and C-termini. Three different forms (a, b, and c) of S100 alpha were produced: with the native sequence, with the initiator methionine at the N-terminus, and with an additional alanine at the C-terminus as well as with the initiator methionine. The material was partly oxidized. Interestingly, only the homodimers of a, b, and c species were formed. The total yield of the protein was about 50 mg/l of culture. Genes coding for Glu32-->Gln and Glu73-->Gln mutants of S100 alpha were obtained by site-directed mutagenesis and expressed in the same system. In both cases similar mixtures of oxidized and reduced a, b, and c species have been obtained. The total yield of E73Q mutant is similar to that of the native protein and that of E32Q lower by about a half. As expected, the mutants of S100 alpha subunits bind only one calcium ion.

The melibiose/Na + symporter of Escherichia coli : kinetic and molecular properties

1990 ◽  
Vol 326 (1236) ◽  
pp. 411-423 ◽  
Keyword(s):  
Escherichia Coli ◽  
Complex Cation ◽  
Expression System ◽  
Binding Activity ◽  
Site Directed Mutagenesis ◽  
Coupling Mechanism ◽  
Facilitated Diffusion ◽  
Histidine Residues ◽  
Sugar Binding ◽  
Dependent Transport

The role of the co-transported cation in the coupling mechanism of the melibiose permease of Escherichia coli has been investigated by analysing its sugar-binding activity, facilitated diffusion reactions and energy-dependent transport reactions catalysed by the carrier functioning either as an H + , Na + or Li + -sugar symporter. The results suggest that the coupling cation not only acts as an activator for sugar-binding on the carrier but also regulates the rate of dissociation of the co-substrates in the cytoplasm by controlling the stability of the ternary complex cation-sugar—carrier facing the cell interior. Furthermore, there is some evidence that the membrane potential enhances the rate of symport activity by increasing the rate of dissociation of the co-substrates from the carrier in the cellular compartment. Identification of the melibiose permease as a membrane protein of 39 kDa by using a T7 RNA polymerase/promoter expression system is described. Site-directed mutagenesis has been used to replace individual carrier histidine residues by arginine to probe the functional contribution of each of the seven histidine residues to the symport mechanism. Only substitution of arginine for His94 greatly interferes with the carrier function. It is finally shown that mutations affecting the glutamate residue in position 361 inactivate translocation of the co-substrates but not their recognition by the permease.

scholarly journals Maturation of the Hepatitis A Virus Capsid Protein VP1 Is Not Dependent on Processing by the 3CproProteinase

1999 ◽  
Vol 73 (8) ◽  
pp. 6220-6227 ◽  
Author(s):  
Annette Martin ◽  
Danièle Bénichou ◽  
Shih-Fong Chao ◽  
Lisette M. Cohen ◽  
Stanley M. Lemon
Keyword(s):  
Capsid Protein ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Expression System ◽  
Site Directed Mutagenesis ◽  
Recognition Sequence ◽  
C Terminus ◽  
Vaccinia Viruses ◽  
Capsid Protein Vp1 ◽  
Vp1 Capsid Protein

ABSTRACT Most details of the processing of the hepatitis A virus (HAV) polyprotein are known. Unique among members of the familyPicornaviridae, the primary cleavage of the HAV polyprotein is mediated by 3Cpro, the only proteinase known to be encoded by the virus, at the 2A/2B junction. All other cleavages of the polyprotein have been considered to be due to 3Cpro, although the precise location and mechanism responsible for the VP1/2A cleavage have been controversial. Here we present data that argue strongly against the involvement of the HAV 3Cproproteinase in the maturation of VP1 from its VP1-2A precursor. Using a heterologous expression system based on recombinant vaccinia viruses directing the expression of full-length or truncated capsid protein precursors, we show that the C terminus of the mature VP1 capsid protein is located near residue 764 of the polyprotein. However, a proteolytically active HAV 3Cpro that was capable of directing both VP0/VP3 and VP3/VP1 cleavages in vaccinia virus-infected cells failed to process the VP1-2A precursor. Using site-directed mutagenesis of an infectious molecular clone of HAV, we modified potential VP1/2A cleavage sites that fit known 3Cprorecognition criteria and found that a substitution that ablates the presumed 3Cpro dipeptide recognition sequence at Glu764-Ser765 abolished neither infectivity nor normal VP1 maturation. Altered electrophoretic mobility of VP1 from a viable mutant virus with an Arg764 substitution indicated that this residue is present in VP1 and that the VP1/2A cleavage occurs downstream of this residue. These data indicate that maturation of the HAV VP1 capsid protein is not dependent on 3Cpro processing and may thus be uniquely dependent on a cellular proteinase.

scholarly journals Expression in Escherichia coli of human ARHGAP6 gene and purification of His-tagged recombinant protein.

2003 ◽  
Vol 50 (1) ◽  
pp. 239-247 ◽  
Author(s):  
Anna-Maria Ochocka ◽  
Marzena Czyzewska ◽  
Tadeusz Pawełczyk
Keyword(s):  
Escherichia Coli ◽  
Fusion Protein ◽  
Rho Gtpase ◽  
Expression System ◽  
Cloning And Expression ◽  
Soluble Form ◽  
E Coli ◽  
Escherichia Coli Cells ◽  
Step Procedure ◽  
Shock Proteins

In this report we describe cloning and expression of human Rho GTPase activating protein (ARHGAP6) isoform 4 in Escherichia coli cells as a fusion protein with 6xHis. We cloned the ARHGAP6 cDNA into the bacterial expression vector pPROEX-1. Induction of the 6xHis-ARHGAP6 protein in BL21(DE3) and DH5alpha cells caused lysis of the cells irrespective of the kind of culture medium used. Successful expression of the fusion protein was obtained in the MC4100Deltaibp mutant strain lacking the small heat-shock proteins IbpA and IbpB. Reasonable yield was obtained when the cells were cultured in Terrific Broth + 1% glucose medium at 22 degrees C for 16 h. The optimal cell density for expression of soluble 6xHis-ARHGAP6 protein was at A(600) about 0.5. Under these conditions over 90% of the fusion protein was present in a soluble form. The 6xHis-ARHGAP6 protein was purified to near homogeneity by a two step procedure comprising chromatography on Ni-nitrilotriacetate and cation exchange columns. The expression system and purification procedure employed made it possible to obtain 1-2 mg of pure 6xHis-ARHGAP6 protein from 300 ml (1.5 g of cells) of E. coli culture.

Cloning and expression in Escherichia coli of a Fasciola hepatica gene encoding a calcium-binding protein

1999 ◽  
Vol 101 (1-2) ◽  
pp. 13-21 ◽  
Author(s):  
Arantxa D. Ruiz de Eguino ◽  
Angeles Machı́n ◽  
Rosa Casais ◽  
Antonio M. Castro ◽  
José A. Boga ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Calcium Binding ◽  
Fasciola Hepatica ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Cloning And Expression ◽  
Gene Encoding ◽  
Expression In Escherichia Coli

scholarly journals Heterologous expression in Escherichia coli of native and mutant forms of the major intrinsic protein of rat eye lens (MIP26)

1995 ◽  
Vol 305 (3) ◽  
pp. 753-759 ◽  
Author(s):  
N Dilsiz ◽  
M J C Crabbe
Keyword(s):  
Escherichia Coli ◽  
Monoclonal Antibody ◽  
Cytoplasmic Membrane ◽  
Amino Acid Level ◽  
Site Directed Mutagenesis ◽  
Eye Lens ◽  
Major Intrinsic Protein ◽  
Intrinsic Protein ◽  
C Terminus ◽  
Cell Plasma

The complete cDNA of rat eye lens major intrinsic protein (MIP26) was sequenced using the dideoxy chain termination method. The sequence displayed 89% nucleotide identity and 95% identity at the amino acid level with bovine MIP26 [Gorin, Yancey, Cline, Revel and Horwitz (1984) Cell, 39, 49-54]. Both native and mutant cDNAs coding for rat MIP26 were amplified by PCR and subcloned into the pPOW expression vector for expression of Escherichia coli. A membrane signal peptide (PelB) was used for secretion of MIP26 into the cytoplasmic membrane. A hydrophilic octapeptide tail (FLAG) was fused to either the N- or C-terminus of MIP26 to aid monoclonal antibody-mediated identification and purification. Heterologously expressed MIP26 was identified by using a monoclonal antibody corresponding to the FLAG peptide located at the termini of MIP26. Immunofluorescently labelled monoclonal antibody was used to determine the localization of MIP26 in the cytoplasmic membrane. The majority of the protein was integrated into cell plasma membrane. MIP26 was extracted with n-octyl beta-D-glucopyranoside and then purified on an affinity gel column. Rat MIP26 cDNA contains an -Asn-Gly- sequence at the C-terminus, which has been shown in other proteins to be particularly susceptible to spontaneous deamidation [Takemoto and Emmons (1991) Curr. Eye Res. 10, 863-869]. We therefore modified the MIP26 molecule using a site-directed mutagenesis method to generate a mutant MIP26 at the appropriate asparagine residue (Asn244-->Asp) near the C-terminus. The mutation was confirmed by DNA sequencing. The mutant MIP26 protein was also expressed in E. coli and incorporated predominantly into the cytoplasmic membrane.

Cloning and Expression of a Synthetic Mussel Adhesive Protein in Escherichia Coli

1992 ◽  
Vol 292 ◽  
Author(s):  
Anthony J. Salerno ◽  
Ina Goldberg
Keyword(s):  
Escherichia Coli ◽  
Soluble Fraction ◽  
Expression System ◽  
Total Cell ◽  
Cloning And Expression ◽  
Vector System ◽  
Cell Protein ◽  
Adhesive Protein ◽  
Mussel Adhesive ◽  
Unit Repeat

AbstractRepetitious gene cassettes that encode the consensus decapeptide repeat of Mytilus edulis bioadhesive protein were cloned and expressed in Escherichia coli. The bioadhesive precursor (BP, Mx−25,000) was expressed from one 600-bp gene comprised of a 30-bp unit repeat. The repetitious gene appeared stable in a T7-based host/vector system.Using the T7 expression system for induction, BP was produced at levels approaching 60% of total cell protein. BP was found both in intracellular inclusions and in the soluble fraction. Interestingly, methionine was processed from the N-terminus of the purified protein to give an authentic consensus precursor protein.

scholarly journals Cloning and expression of LTB in Escherichia coli and Bacillus subtilis

2013 ◽  
Vol 16 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Trang Thi Phuong Phan ◽  
Anh Le Tuan Nguyen ◽  
Hoang Duc Nguyen
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Fusion Protein ◽  
Expression System ◽  
Pharmaceutical Products ◽  
Cloning And Expression ◽  
Gene Encoding ◽  
E Coli ◽  
B Subunit ◽  
The Common

LTB is the B subunit of heat labile toxins (LT) in Escherichia coli ETEC. This subunit is non-toxic but has a high immune response. Therefore, LTB is considered a suitable antigen for partial vaccine against the diarrhea caused by E. coli ETEC. The most important component of partial vaccine is antigen protein. Nowadays, with the advancement of recombinant protein technology, these antigens are mainly produced by the common bacterial expression system as E. coli. However, the recombinant proteins produced by E. coli are often miscellaneous with enterotoxins, which should be removed from pharmaceutical products. Thus, the production of antigen proteins in other expression system without endotoxins like Bacillus subtilis is in attention. We conducted the experiments of cloning and expressing LTB using a novel pHT plasmid that allow the protein to be expressed in both of E. coli and B. subtilis. We were successful to generate plasmid pHT326 and express the gene encoding for the fusion protein of LTB and LysSN-6xHis-TEV in B. subtilis and E. coli. The binding of fusion protein on the columns that have affinity with His-tag was confirmed. This result is about to be applied for the development of partial vaccine aganst the diarrhea as well as the development of some diagnostic kits for ETEC in food or medical waste and kits to detect antibodies against LTB in animals.

Cloning and expression of the beta-D-phosphogalactoside galactohydrolase gene of Lactobacillus casei in Escherichia coli K-12

1982 ◽  
Vol 152 (3) ◽  
pp. 1138-1146
Author(s):  
L J Lee ◽  
J B Hansen ◽  
E K Jagusztyn-Krynicka ◽  
B M Chassy
Keyword(s):  
Escherichia Coli ◽  
Lactobacillus Casei ◽  
Specific Activity ◽  
Protein Product ◽  
Coli Strain ◽  
Cloning And Expression ◽  
E Coli ◽  
Lactose Metabolism ◽  
Gene Coding ◽  
K 12

Lactose metabolism in Lactobacillus casei 64H is associated with the presence of plasmid pLZ64. This plasmid determines both phosphoenolpyruvate-dependent phosphotransferase uptake of lactose and beta-D-phosphogalactoside galactohydrolase. A shotgun clone bank of chimeric plasmids containing restriction enzyme digest fragments of pLZ64 DNA was constructed in Escherichia coli K-12. One clone contained the gene coding for beta-D-phosphogalactoside galactohydrolase on a 7.9-kilobase PstI fragment cloned into the vector pBR322 in E. coli strain chi 1849. The beta-D-phosphogalactoside galactohydrolase enzyme isolated from E. coli showed no difference from that isolated from L. casei, and specific activity of beta-D-phosphogalactoside galactohydrolase was stimulated 1.8-fold in E. coli by growth in media containing beta-galactosides. A restriction map of the recombinant plasmid was compiled, and with that information, a series of subclones was constructed. From an analysis of the proteins produced by minicells prepared from transformant E. coli cells containing each of the recombinant subclone plasmids, it was found that the gene for the 56-kilodalton beta-D-phosphogalactoside galactohydrolase was transcribed from an L. casei-derived promoter. The gene for a second protein product (43 kilodaltons) was transcribed in the opposite direction, presumably under the control of a promoter in pBR322. The relationship of this second product to the lactose metabolism genes of L. casei is at present unknown.

scholarly journals Cloning and expression of a gene coding for the prolipoprotein signal peptidase of Escherichia coli

FEBS Letters ◽  
1983 ◽  
Vol 158 (2) ◽  
pp. 301-304 ◽  
Author(s):  
Hideo Yamagata ◽  
Kyoko Daishima ◽  
Shoji Mizushima
Keyword(s):  
Escherichia Coli ◽  
Cloning And Expression ◽  
Signal Peptidase ◽  
Gene Coding
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