scholarly journals Preparation and characterization of bovine growth hormones produced in recombinant Escherichia coli

1987 ◽  
Vol 243 (3) ◽  
pp. 829-839 ◽  
Author(s):  
P T Wingfield ◽  
P Graber ◽  
G Buell ◽  
K Rose ◽  
M G Simona ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Recombinant Dna ◽  
Polyacrylamide Gel Electrophoresis ◽  
Full Length ◽  
Sds Page ◽  
Rat Tibia ◽  
Bovine Sequence ◽  
Recombinant Dna Techniques

Two analogues of bovine growth hormone (BGH) have been produced in Escherichia coli by recombinant DNA techniques. In analogue Delta-1, the N-terminal alanine residue of the full-length bovine sequence is replaced by methionine. In analogue Delta-9, which is expressed at much higher levels than is Delta-1, the full-length bovine sequence is truncated at the N-terminus by eight residues and there is a serine-for-glycine substitution in the first position of the truncated protein. Both analogues, which were characterized by isoelectric focusing (i.e.f.), polyacrylamide-gel electrophoresis in the presence of SDS (SDS/PAGE), amino acid analysis and N-terminal amino acid sequence determination using combined g.l.c.-m.s., are compared with BGH isolated from pituitaries. In contrast with pituitary-derived BGH, the recombinant-derived proteins are homogeneous on SDS/PAGE and on i.e.f. In a radioimmunoassay, a radioreceptor assay and a bioassay in vivo (rat tibia), Delta-9 BGH showed very similar characteristics to the pituitary-derived hormone. Similar results have also been obtained with the Delta-1 analogue.

scholarly journals Influenza virus hemagglutinin-specific cytotoxic T cell response induced by polypeptide produced in Escherichia coli.

1985 ◽  
Vol 162 (2) ◽  
pp. 663-674 ◽  
Author(s):  
A Yamada ◽  
M R Ziese ◽  
J F Young ◽  
Y K Yamada ◽  
F A Ennis
Keyword(s):  
Influenza Virus ◽  
Recombinant Dna ◽  
Cytotoxic T Lymphocyte ◽  
Nonstructural Protein ◽  
T Cell Response ◽  
Cytotoxic T Cell ◽  
Protein Immunization ◽  
Recombinant Dna Techniques

We have tested the abilities of various polypeptides of A/PR/8/34 (H1N1) virus, constructed by recombinant DNA techniques, to induce influenza virus-specific secondary cytotoxic T lymphocyte (CTL) responses. A hybrid protein (c13 protein), consisting of the first 81 amino acids of viral nonstructural protein (NS1) and the HA2 subunit of viral hemagglutinin (HA), induced H-2-restricted, influenza virus subtype-specific secondary CTL in vitro, although other peptides did not. Using a recombinant virus, the viral determinant responsible for recognition was mapped to the HA2 portion of c13 protein. Immunization of mice with c13 protein induced the generation of memory CTL in vivo. The CTL precursor frequencies of A/PR/8/34 virus- and c13 protein-immune mice were estimated as one in 8,047 and 50,312, respectively. These results indicate that c13 protein primed recipient mice, even though the level of precursor frequency was below that observed in virus-immune mice.

scholarly journals Isolation and Characterization of Two Proteins fromMoraxella catarrhalis That Bear a Common Epitope

1998 ◽  
Vol 66 (9) ◽  
pp. 4374-4381 ◽  
Author(s):  
John C. McMichael ◽  
Michael J. Fiske ◽  
Ross A. Fredenburg ◽  
Deb N. Chakravarti ◽  
Karl R. VanDerMeid ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Bacterial Attachment ◽  
Vaccine Candidates ◽  
Isolation And Characterization ◽  
Sds Page

ABSTRACT The UspA1 and UspA2 proteins of Moraxella catarrhalisare potential vaccine candidates for preventing disease caused by this organism. We have characterized both proteins and evaluated their vaccine potential using both in vitro and in vivo assays. Both proteins were purified from the O35E isolate by Triton X-100 extraction, followed by ion-exchange and hydroxyapatite chromatography. Analysis of the sequences of internal peptides, prepared by enzymatic and chemical cleavage of the proteins, revealed that UspA1 and UspA2 exhibited distinct structural differences but shared a common sequence including an epitope recognized by the monoclonal antibody 17C7. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), purified UspA1 exhibited a molecular weight of approximately 350,000 when unheated and a molecular weight of 100,000 after being heated for 10 min at 100°C. In contrast, purified UspA2 exhibited an apparent molecular weight of 240,000 by SDS-PAGE that did not change with the length of time of heating. Their sizes as determined by gel filtration were 1,150,000 and 830,000 for UspA1 and UspA2, respectively. Preliminary results indicate the proteins have separate functions in bacterial pathogenesis. Purified UspA1 was found to bind HEp-2 cells, and sera against UspA1, but not against UspA2, blocked binding of the O35E isolate to the HEp-2 cells. UspA1 also bound fibronectin and appears to have a role in bacterial attachment. Purified UspA2, however, did not bind fibronectin but had an affinity for vitronectin. Both proteins elicited bactericidal antibodies in mice to homologous and heterologous disease isolates. Finally, mice immunized with each of the proteins, followed by pulmonary challenge with either the homologous or a heterologous isolate, cleared the bacteria more rapidly than mock-immunized mice. These results suggest that UspA1 and UspA2 serve different virulence functions and that both are promising vaccine candidates.

scholarly journals Heterologous Expression and Characterization of A Novel Ochratoxin A Degrading Enzyme, N-acyl-L-amino Acid Amidohydrolase, from Alcaligenes faecalis

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 518
Author(s):  
Honghai Zhang ◽  
Yunpeng Zhang ◽  
Tie Yin ◽  
Jing Wang ◽  
Xiaolin Zhang
Keyword(s):  
Amino Acid ◽  
Ochratoxin A ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Alcaligenes Faecalis ◽  
Degrading Enzyme ◽  
Sds Page ◽  
Ochratoxin Α ◽  
Acid Amidohydrolase

Ochratoxin A (OTA) is a well-known, natural contaminant in foods and feeds because of its toxic effects, such as nephrotoxicity in various animals. Recent studies have revealed that Alcaligenes faecalis could generate enzymes to efficiently degrade OTA to ochratoxin α (OTα) in vitro. In an effort to obtain the OTA degrading mechanism, we purified and identified a novel degrading enzyme, N-acyl-L-amino acid amidohydrolase (AfOTase), from A. faecalis DSM 16503 via mass spectrometry. The same gene of the enzyme was also encountered in other A. faecalis strains. AfOTase belongs to peptidase family M20 and contains metal ions at the active site. In this study, recombination AfOTase was expressed and characterized in Escherichia coli. The molecular mass of recombinant rAfOTase was approximately 47.0 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme exhibited a wide temperature range (30–70 °C) and pH adaptation (4.5–9.0) and the optimal temperature and pH were 50 °C and 6.5, respectively.

DNA Colony Hybridization Method Using Synthetic Oligonucleotides to Detect Enterotoxigenic Escherichia coli: Collaborative Study

1986 ◽  
Vol 69 (3) ◽  
pp. 531-536
Author(s):  
Walter E Hill ◽  
Barry A Wentz ◽  
William L Payne ◽  
James A Jagow ◽  
Gerald Zon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Recombinant Dna ◽  
Collaborative Study ◽  
Dna Probes ◽  
Enterotoxigenic Escherichia Coli ◽  
Hybridization Probe ◽  
Colony Hybridization ◽  
E Coli ◽  
Calf Thymus ◽  
Recombinant Dna Techniques

Abstract The genes that encode several of the enterotoxins produced by Escherichia coli have been cloned by recombinant DNA techniques. When the nucleotide sequence of these genes is determined, defined sequence oligonucleotides that include a part of these genes may be synthesized. A 22-base DNA hybridization probe was produced for each of 2 heatstable E. coli enterotoxin (ST) genes: STH, from strains originally isolated from humans; and STP, from strains first found in pigs. For this study, 32P end-labeled DNA probes, sonicated calf thymus DNA, and 3 known and 20 unknown (10 ST-positive and 10 ST-negative) strains were sent to each of 23 collaborators. Cultures were spotted onto an agar-based medium and grown into colonies, which were transferred by blotting to cellulose filters, lysed by alkali and steam, and used for DNA colony hybridization with the ST DNA probes. Strains containing an ST gene were recognized as dark spots on an autoradiogram. Of the 460 samples analyzed, 440 (95.7%) were correctly classified by the collaborators. The method has been adopted official first action.

scholarly journals Identification of a Kinase-Active CheA Conformation in Escherichia coli Chemoreceptor Signaling Complexes

2019 ◽  
Vol 201 (23) ◽  
Author(s):  
Germán E. Piñas ◽  
John S. Parkinson
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Kinase Activity ◽  
Critical Role ◽  
Active State ◽  
Dynamics Simulation ◽  
Cross Linking ◽  
Atp Binding ◽  
Content Type

ABSTRACT Escherichia coli chemotaxis relies on control of the autophosphorylation activity of the histidine kinase CheA by transmembrane chemoreceptors. Core signaling units contain two receptor trimers of dimers, one CheA homodimer, and two monomeric CheW proteins that couple CheA activity to receptor control. Core signaling units appear to operate as two-state devices, with distinct kinase-on and kinase-off CheA output states whose structural nature is poorly understood. A recent all-atom molecular dynamic simulation of a receptor core unit revealed two alternative conformations, “dipped” and “undipped,” for the ATP-binding CheA.P4 domain that could be related to kinase activity states. To explore possible signaling roles for the dipped CheA.P4 conformation, we created CheA mutants with amino acid replacements at residues (R265, E368, and D372) implicated in promoting the dipped conformation and examined their signaling consequences with in vivo Förster resonance energy transfer (FRET)-based kinase assays. We used cysteine-directed in vivo cross-linking reporters for the dipped and undipped conformations to assess mutant proteins for these distinct CheA.P4 domain configurations. Phenotypic suppression analyses revealed functional interactions among the conformation-controlling residues. We found that structural interactions between R265, located at the N terminus of the CheA.P3 dimerization domain, and E368/D372 in the CheA.P4 domain played a critical role in stabilizing the dipped conformation and in producing kinase-on output. Charge reversal replacements at any of these residues abrogated the dipped cross-linking signal, CheA kinase activity, and chemotactic ability. We conclude that the dipped conformation of the CheA.P4 domain is critical to the kinase-active state in core signaling units. IMPORTANCE Regulation of CheA kinase in chemoreceptor arrays is critical for Escherichia coli chemotaxis. However, to date, little is known about the CheA conformations that lead to the kinase-on or kinase-off states. Here, we explore the signaling roles of a distinct conformation of the ATP-binding CheA.P4 domain identified by all-atom molecular dynamics simulation. Amino acid replacements at residues predicted to stabilize the so-called “dipped” CheA.P4 conformation abolished the kinase activity of CheA and its ability to support chemotaxis. Our findings indicate that the dipped conformation of the CheA.P4 domain is critical for reaching the kinase-active state in chemoreceptor signaling arrays.

scholarly journals Characterization of antithrombins produced by active site mutagenesis of human alpha 1-antitrypsin expressed in yeast

Blood ◽  
1989 ◽  
Vol 73 (2) ◽  
pp. 490-496 ◽  
Author(s):  
PM George ◽  
P Pemberton ◽  
IC Bathurst ◽  
RW Carrell ◽  
HL Gibson ◽  
...  
Keyword(s):  
Active Site ◽  
Recombinant Dna ◽  
Thrombin Inhibition ◽  
Congenital Deficiency ◽  
At Iii ◽  
Alpha 1 Antitrypsin ◽  
Recombinant Dna Techniques ◽  
Site Mutagenesis

Abstract Both congenital and acquired antithrombin-III (AT-III) deficiencies are amenable to replacement therapy. We describe two antithrombins produced by recombinant DNA techniques from human alpha 1-antitrypsin (alpha 1AT) cDNA in yeast. Alteration of the alpha 1AT active site, replacing methionine 358 with arginine, results in a thrombin inhibition rate similar to that of heparin-activated AT-III. Alteration of two further residues, to give a five-residue sequence identical to AT-III, does not increase this rate further. Neither antithrombin is activated by heparin; both are unglycosylated and have shorter in vivo half-lives (t1/2) than human alpha 1AT. These antithrombins should be suitable for therapeutic replacement of AT-III in cases of congenital deficiency and in conditions associated with acquired AT-III deficiency, such as disseminated intravascular coagulation.

Isolation of Labeled Lipoprotein from Escherichia coli and Proteus mirabilis after Incubation with [14C]Penicillin

1985 ◽  
Vol 40 (5-6) ◽  
pp. 415-420 ◽  
Author(s):  
Gerhard Gruner ◽  
Monier H. Tadros ◽  
Roland Plapp
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Proteus Mirabilis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Apparent Molecular Weight ◽  
Penicillin G ◽  
Free Form ◽  
E Coli

Abstract [14C]penicillin binding experiments and membrane analysis were carried out with cell envelope preparations from Escherichia coli and Proteus mirabilis. After incubation with [14C] penicillin G labeled free lipoprotein could be identified. The analysis of the isolated lipoprotein by SDS polyacrylamide gel electrophoresis indicates that there is only one protein with an apparent molecular weight of 7000. The amino acid composition of isolated labeled free lipoprotein from E. coli was identical to the lipoprotein already found in E. coli. It is a point of interest that the amino acid composition of the isolated labeled free lipoprotein from P. mirabilis D52 differs from that found in other mutants of this strain. The free form of lipoprotein from P. mirabilis D52 is composed of 61 amino acids and has glycine, phenylalanine and proline as specific components.

PROTEIN C IS ACTIVATED AND GIVES 110,000 MW COMPLEXES AND PROTEIN S IS CLEAVED AND DECREASED _IN VIVO IN PATIENTS WITH INTRAVASCULAR COAGULATION (DIC)

1987 ◽  
Author(s):  
M J Heeb ◽  
D F Mosher ◽  
J H Griffin
Keyword(s):  
Protein C ◽  
Degradation Products ◽  
Polyacrylamide Gel Electrophoresis ◽  
Severe Infection ◽  
Apparent Molecular Weight ◽  
Protein S ◽  
Entire Group ◽  
Normal Plasma ◽  
Sds Page

Immunoblotting studies using denaturing and nondenaturing polyacrylamide gel electrophoresis conditions were performed on 100 plasmas from 88 patients with suspected DIC, in order to determine whether the anticoagulant regulatory proteins C and S (PC and PS) cure altered in vivo during DIC. 70 of these plasmas from 65 patients contained 5-35% of PC antigen in the form of activated protein C (APC) complexed with inhibitor(s).24 normal plasmas showed no detectable APC-inhibitor complexes.The complexes in DIC plasmas had a MW of 110 K on SDS-PAGE, as did complexes formed when APC was incubated with plasma immunodepleted of PC, or when PC in normal plasma was activated with Protac C. On nondenaturing gels, the complex present in 69 of 70 patient plasmas had the same mobility as one of two major bands of complexed APC observed in Protac C-activated normal plasma. One patient plasma contained two forms of PC antigen complex. This patient had suffered a perforated uterus during an abortion. After Protac C activation of the patient plasmas, two APC complexed bands were seen. The 16 patients with >15% complexed PC antigen included 3 with severe infection, 5 with solid tumors, 3 with leukemias, 2 with vascular disease and 3 with other diagnoses. These patients had a higher mortality (69%) than the group as a whole and higher levels of fibrin degradation products. 13 of these 16 plasmas and 56 of the entire group of 100 contained a higher than normal proportion of PS in a cleaved form with an apparent molecular weight lower than intact PS on reduced SDS-PAGE. Mean levels of PS antigen determined by electroimmunoassay for 95 of the plasmas were as follows: entire group, 86% (92%); patients with infection (n=34), 76% (81%); patients with malignancy (n=37), 102% (105%); all others (n=24), 70% (74%) wherfe numbers in parentheses exclude patients with liver disease and 100% normal pooled plasma. These studies suggest that PS is cleaved and decreased in vivo and that PC is activated in vivo and complexed with a 50K MW inhibitor(s) during DIC.

scholarly journals Purification and Characterization of the Recombinant Thermus sp. Strain T2 α-Galactosidase Expressed in Escherichia coli

2001 ◽  
Vol 67 (4) ◽  
pp. 1601-1606 ◽  
Author(s):  
Mitsunori Ishiguro ◽  
Satoshi Kaneko ◽  
Atsushi Kuno ◽  
Yoshinori Koyama ◽  
Shigeki Yoshida ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Active Form ◽  
Gel Filtration ◽  
Amino Acid Sequences ◽  
Side Chain ◽  
Catalytic Function ◽  
Native Polyacrylamide Gel Electrophoresis

ABSTRACT The nucleotide sequence of the Thermus sp. strain T2 DNA coding for a thermostable α-galactosidase was determined. The deduced amino acid sequence of the enzyme predicts a polypeptide of 474 amino acids (M r, 53,514). The observed homology between the deduced amino acid sequences of the enzyme and α-galactosidase from Thermus brockianus was over 70%.Thermus sp. strain T2 α-galactosidase was expressed in its active form in Escherichia coli and purified. Native polyacrylamide gel electrophoresis and gel filtration chromatography data suggest that the enzyme is octameric. The enzyme was most active at 75°C forp-nitrophenyl-α-d-galactopyranoside hydrolysis, and it retained 50% of its initial activity after 1 h of incubation at 70°C. The enzyme was extremely stable over a broad range of pH (pH 6 to 13) after treatment at 40°C for 1 h. The enzyme acted on the terminal α-galactosyl residue, not on the side chain residue, of the galactomanno-oligosaccharides as well as those of yeasts and Mortierella vinacea α-galactosidase I. The enzyme has only one Cys residue in the molecule.para-Chloromercuribenzoic acid completely inhibited the enzyme but did not affect the mutant enzyme which contained Ala instead of Cys, indicating that this Cys residue is not responsible for its catalytic function.

scholarly journals Bacteriocin-Like Activity of Butyrivibrio fibrisolvens JL5 and Its Effect on Other Ruminal Bacteria and Ammonia Production

2002 ◽  
Vol 68 (3) ◽  
pp. 1040-1046 ◽  
Author(s):  
Jennifer L. Rychlik ◽  
James B. Russell
Keyword(s):  
Amino Acid ◽  
Potassium Level ◽  
Polyacrylamide Gel Electrophoresis ◽  
Electrical Potential ◽  
Molecular Size ◽  
Ammonia Production ◽  
Ruminal Bacteria ◽  
Butyrivibrio Fibrisolvens ◽  
Atp Level

ABSTRACT When ruminal bacteria from a cow fed hay were serially diluted into an anaerobic medium that had only peptides and amino acids as energy sources, little growth or ammonia production was detected at dilutions greater than 10−6. The 10−8 and 10−9 dilutions contained bacteria that fermented carbohydrates, and some of these bacteria inhibited Clostridium sticklandii SR, an obligate amino acid-fermenting bacterium. Phylogenetic analysis indicated that the most active isolate (JL5) was closely related to Butyrivibrio fibrisolvens B835. Strain JL5 inhibited B. fibrisolvens 49 and a variety of other gram-positive organisms, but it had little effect on most gram-negative ruminal bacteria. Strain JL5 did not produce a bacteriocin-like inhibitory substance (BLIS) until it reached the late log or stationary phase. The JL5 BLIS did not cause the lysis of B. fibrisolvens 49, but the intracellular potassium level, the ATP level, the electrical potential, and the viability decreased rapidly. The JL5 BLIS also caused marked decreases in the viability and cellular potassium level of C. sticklandii SR. The membrane potential and intracellular ATP level also declined. The BLIS was degraded very slowly by pronase E, but it could be precipitated with 60% ammonium sulfate and dialyzed (3,500-Da cutoff). The BLIS could be separated from other peptides by polyacrylamide gel electrophoresis, and C. sticklandii SR overlays indicated that the molecular size of this compound was approximately 3,600 Da. Based on these results, it appeared that the JL5 BLIS was a pore-forming peptide. Because carbohydrate-fermenting ruminal bacteria could inhibit the growth of obligate amino acid-fermenting bacteria, BLIS may play a role in regulating ammonia production in vivo.

Sign in / Sign up

Export Citation Format

Share Document