Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The RNA genome of foot- and mouth disease virus strains A5 Westerwald and O1 Lausanne has been reverse-transcribed and cloned in lambdaphages or plasmids. Identification of cDNA-clones containing VP1-specific sequences was achieved by hybridization, restriction mapping, and sequence analysis. VP1-coding cDNA-fragments were subcloned into the expression vector pEX which led to synthesis of fusion proteins with beta-galactosidase. These fusion proteins reacted with anti-VP1 antibodies on a Western blot, but were not capable of inducing neutralizing antibodies to mice. This seemed to suggest a tertiary structure of the VP1-epitopes unlike those of native VP1. Other attempts are discussed to construct VP1-fusion proteins folding similarly to the native viral protein structure.
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PMID:cDNA-cloning and expression of VP1-specific sequences of foot-and-mouth disease virus types A5 and O1. 196 57

Part of the genome of foot-and-mouth disease virus (FMDV) type 01,BFS, including the sequence encoding the capsid polypeptide VP1, was cloned in Escherichia coli following a new cloning strategy. The clone containing the VP1 sequence was used for the construction of two expression plasmids encoding VP1 fusion proteins. Subsequently, substantial amounts of the two VP1-beta-galactosidase fusion proteins, containing either one (amino acid region 140-160) or two (amino acid regions 140-160 and 200-213) antigenic determinants of the virus, were synthesized by E. coli bacteria. The protein containing the amino acid region 140-160 of VP1 fused to beta-galactosidase efficiently induced antibodies in rabbits specifically reacting with FMDV type 01,BFS. The same protein was also capable of eliciting neutralizing antibodies. The fusion protein containing both antigenic determinants did not efficiently induce antibodies reacting with FMDV.
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PMID:Synthesis of fusion proteins containing antigenic determinants of foot-and-mouth disease virus. 242 5

A series of four expression plasmids coding for fusion proteins containing foot-and-mouth disease virus (FMDV) sequences was constructed. The fusion proteins contain a large part of beta-galactosidase from Escherichia coli preceded (N-terminal) by 1, 2, 4 or 8 repeats of the antigenic determinant of FMDV consisting of amino acids 137-162 of the capsid polypeptide VP1. All four fusion proteins were efficiently produced in E. coli host bacteria. Immunization of rabbits resulted in FMDV-specific, neutralizing antibodies, the response being dependent on the number of repeats. With enzyme-linked immunosorbent-assay techniques it was shown that the FMDV antigenic determinants are exposed on the surface of the fusion proteins under non-denaturing conditions.
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PMID:Synthesis of fusion proteins with multiple copies of an antigenic determinant of foot-and-mouth disease virus. 243 76

Proteins consisting of one, two or four copies of the amino acid sequence 137 to 162, which contains the major immunogenic site of VP1 of foot-and-mouth disease virus, attached to the N-terminus of beta-galactosidase have been expressed in Escherichia coli cells. In guinea-pigs the protein containing one copy (P71) of the viral determinant elicited only low levels of neutralizing antibody whereas protective levels were elicited by the proteins containing two (P72) or four (P74) copies of the determinant. Single inoculations of the P72 and P74 proteins containing as little as 2 micrograms or 0.8 micrograms of peptide respectively were sufficient to protect all the animals against challenge infection. Moreover, the equivalent of 40 micrograms of peptide in P74 protected pigs against challenge infection after one inoculation.
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PMID:Fusion proteins with multiple copies of the major antigenic determinant of foot-and-mouth disease virus protect both the natural host and laboratory animals. 244 25

Plasmids have been constructed which contain genes coding for fused proteins including beta-galactosidase or human leukocyte interferon alpha 2 and monomeric or pentameric form of the main antigenic determinant of the foot-and-mouth disease virus (FMDV) serotype 01K. Expression of the hybrid genes has been studied. It is shown that fused proteins, containing beta-galactosidase and the antigenic determinant (monomer or pentamer), interact specifically with anti-FMDV anti-sera and with antibodies against peptide 141-160 of FMDV VP1 coat protein.
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PMID:[Recombinant plasmids containing hybrid protein genes with antigenic determinants of the foot and mouth virus]. 247 57

A fusion protein consisting of beta-galactosidase (GZ) to which was attached at its N-terminus the amino acid sequence corresponding to residues 142-160 of the immunogenic protein VP1 of foot-and-mouth disease virus (FMDV) has been expressed in E. coli. A chemically synthesized section of DNA corresponding to the amino acid sequence 142-160 was inserted into a vector (pXY410) designed to express fusion proteins with the carboxy terminal 1015 amino acids of GZ. The hybrid protein immunopurified by a GZ-specific monoclonal antibody was soluble, retained full GZ activity, and induced virus-neutralizing antibody in guinea pigs and mice. There were significant differences between the responses of individual mice to the FMDV peptide sequence, although the titers against GZ were uniformly high. This variable pattern did not change after hyperimmunization and was demonstrable in a range of mouse strains of different haplotype. The same results were obtained whether the response was measured by virus neutralization or by RIA against the FMDV peptide sequence. The possible reasons for the variable recognition of the FMDV epitopes by individual mice are discussed.
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PMID:Bacterially expressed antigenic peptide from foot-and-mouth disease virus capsid elicits variable immunologic responses in animals. 300 1

A simple method for monitoring and quantifying automatically the production by fermentation of beta-galactosidase fusion proteins, making use of the remaining activity of the beta-galactosidase part, is considered. A hybrid protein carrying the major antigenic domain of foot-and-mouth disease virus C1 joined at the N-terminus of beta-galactosidase has been expressed in Escherichia coli. The yield of the chimeric protein has been monitored by flow injection analysis (FIA) during batch fermentations at laboratory scale, and a high correlation between values of product concentration from FIA and from immunological quantizations has been obtained. Because of the possibility of employing FIA in large-scale experiments, and the high sampling frequency, versatility, and reproducibility offered by this method, we propose FIA as a general, simple, quick, flexible, and reliable instrument for both monitoring the yield of recombinant proteins produced industrially, and performing basic research at laboratory scale.
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PMID:Uses of beta-galactosidase tag in on-line monitoring production of fusion proteins and gene expression in Escherichia coli. 776 38

The ompA genes of Escherichia coli and Shigella dysenteriae have been used to construct a group of enterobacterial surface expression vectors for foreign genes. Linker oligonucleotides were inserted into the sequence corresponding to the third or fourth outer domain to allow in-frame sandwich fusion of foreign genes or epitopes into ompA. Influenza haemagglutinin was inserted without its leader peptide and anchor sequences and shown to be transferred as an ompA fusion protein to the bacterial surface in large amounts. The stability of this system depends on the stem structure (i.e. the bottom part) of the haemagglutinin unit which apparently initiates the folding process that extends into the ompA segment. This fusion construct can be used as a vector system and has been used to transfer to the bacterial surface several other proteins inserted into it, including beta-galactosidase, foot-and-mouth disease virus (FMDV) and malaria antigens. All are exported from the cytoplasm across both the inner and outer membranes to become exposed on the bacterial surface. Very hydrophobic segments or inserts with distinct secondary structures, such as the capsid protein, VP1 of FMDV, will, however, block this process.
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PMID:OmpA fusion proteins for presentation of foreign antigens on the bacterial outer membrane. 779 62

Seven internal, putatively exposed regions of Escherichia coli beta-galactosidase have been explored regarding their tolerance to insertions of large foreign peptides. Small sequence modifications, including amino acid substitutions and small deletions, were introduced into the lacZ gene to generate unique BamHI restriction sites. By using these mutant genes, a 27 amino acid stretch reproducing the hypervariable loop of foot-and-mouth disease virus VP1 protein (site A) was further inserted in predefined regions of the enzyme. Among the 13 resulting engineered proteins only three, carrying sequence modifications within a short region, are active, with only moderate reduction of their specific activities. The identified permissive region, which involves amino acids 275 to 279, seems to be a flexible area that could be appropriate to incorporate and study biological properties of heterologous peptides in correctly folded beta-galactosidase chimeric proteins.
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PMID:Insertion of a 27 amino acid viral peptide in different zones of Escherichia coli beta-galactosidase: effects on the enzyme activity. 798 75

The main antigenic region of foot-and-mouth disease virus serotype C1, also called site A, has been inserted in zones of the beta-galactosidase important for the stabilization of the active site, causing important changes in the Km and the specific activity of the resulting enzymes. The peptide is displayed at the surface of the recombinant proteins and, in all the cases, presents a good antigenicity. Among the recombinant proteins constructed, in proteins M278VP1 and M275SVP1 the peptide is inserted in a large loop of the beta-galactosidase (amino acids 272-288) involved in the formation of the activating interface. In these constructs, the binding of the specific antibodies directed to the foreign peptide causes an increase of the beta-galactosidase activity up to about 200%. This phenomenon has been proved using monoclonal antibodies and also using polyclonal sera generated against the peptide. Different hypothesis of the mechanism of modulation upon antibody binding are discussed. This insertion site seems to be sensitive enough to enzymatic modulation mediated by antibody binding. We propose further exploring this insertion site as a tool for a rapid detection of specific antibodies in a quick and simple homogeneous assay based on the colorimetric determination of beta-galactosidase activity.
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PMID:Beta-galactosidase enzymatic activity as a molecular probe to detect specific antibodies. 870 99


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