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:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previously we demonstrated that a novel stress protein is induced in fish cells by the infection of a fish rhabdovirus (Cho W. J., Cha, S. J., Do, J. W., Choi, J. Y., Lee, J. Y., Jeong, C. S., Cho, K. J., Choi, W. S., Kang, H. S., Kim, H. D., and Park, J. W. (1997) Biochem. Biophys. Res. Commun. 233, 316-319). In this paper, we present the molecular cloning and characterization of a gene encoding this protein named virus-inducible stress protein (VISP). The VISP was purified partially by immunoprecipitation using a monoclonal antibody against the VISP and further purified by the electroelution from a SDS-PAGE gel. The protein was subjected to internal protein sequencing, and the sequence of three peptides was determined. Degenerate oligonucleotides based on the three peptide sequences were used to screen a cDNA library from rhabdovirus-infected CHSE-214 fish cells, and a cDNA of a 2193-bp open reading frame encoding the VISP with 730 amino acid residues (M(r) = 79.84) was identified. Whereas the nucleotide sequence of VISP shows no similarity with other genes in the GenBank(TM), the amino acid sequence of the VISP has similarity with the bacterial extracellular solute-binding protein family 5 (SBP_bac_5) that is proposed to have chaperone activity. Thus, we explored whether the VISP also had chaperone-like activity. Purified recombinant VISP expressed in Escherichia coli promoted the functional folding of alpha-glucosidase after urea denaturation and also prevented thermal aggregation of alcohol dehydrogenase. These results suggest that the VISP has amino acid sequence similarity with SBP_bac_5 and that it has chaperone activity that may play a role in virus infection.
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PMID:Molecular cloning of a novel chaperone-like protein induced by rhabdovirus infection with sequence similarity to the bacterial extracellular solute-binding protein family 5. 1218 66

Spectrin, the major constituent protein of the erythrocyte membrane skeleton, exhibits chaperone activity by preventing the irreversible aggregation of insulin at 25 degrees C and that of alcohol dehydrogenase at 50 degrees C. The dimeric spectrin and the two subunits, alpha-spectrin and beta-spectrin prevent such aggregation appreciably better, 70% in presence of dimeric spectrin at an insulin:spectrin ratio of 1:1, than that in presence of the tetramer of 25%. Our results also show that spectrin binds to denatured enzymes alpha-glucosidase and alkaline phosphatase during refolding and the reactivation yields are increased in the presence of the spectrin derivatives when compared with those refolded in their absence. The unique hydrophobic binding site on spectrin for the fluorescence probe, 6-propionyl-2-(dimethylamino)naphthalene (Prodan) has been established to localize at the self-associating domain with the binding stoichiometry of one Prodan/both dimeric and tetrameric spectrin. The other fluorescence probe, 1-anilinonaphthalene-8-sulfonic acid, does not show such specificity for spectrin, and the binding stoichiometry is between 3 and 5 1-anilinonaphthalene-8-sulfonic acid/dimeric and tetrameric spectrin, respectively. Regions in alpha- and beta-spectrins have been found to have sequence homology with known chaperone proteins. More than 50% similarities in alpha-spectrin near the N terminus with human Hsp90 and in beta-spectrin near the C terminus with human Hsp90 and Escherichia coli DnaJ have been found, indicating a potential chaperone-like sequence to be present near the self-associating domain that is formed by portions of alpha-spectrin near the N terminus and the beta-spectrin near the C terminus. There are other patches of sequences also in both the spectrin polypeptides, at the other termini as well as in the middle of the rod domain having significant homology with well known chaperone proteins.
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PMID:Chaperone activity and prodan binding at the self-associating domain of erythroid spectrin. 1549 10

Intracellular products, not secreted from the microbial cell, are released by breaking the cell envelope consisting of cytoplasmic membrane and an outer cell wall. Hydrodynamic cavitation has been reported to cause microbial cell disruption. By manipulating the operating variables involved, a wide range of intensity of cavitation can be achieved resulting in a varying extent of disruption. The effect of the process variables including cavitation number, initial cell concentration of the suspension and the number of passes across the cavitation zone on the release of enzymes from various locations of the Brewers' yeast was studied. The release profile of the enzymes studied include alpha-glucosidase (periplasmic), invertase (cell wall bound), alcohol dehydrogenase (ADH; cytoplasmic) and glucose-6-phosphate dehydrogenase (G6PDH; cytoplasmic). An optimum cavitation number Cv of 0.13 for maximum disruption was observed across the range Cv 0.09-0.99. The optimum cell concentration was found to be 0.5% (w/v, wet wt) when varying over the range 0.1%-5%. The sustained effect of cavitation on the yeast cell wall when re-circulating the suspension across the cavitation zone was found to release the cell wall bound enzyme invertase (86%) to a greater extent than the enzymes from other locations of the cell (e.g. periplasmic alpha-glucosidase at 17%). Localised damage to the cell wall could be observed using transmission electron microscopy (TEM) of cells subjected to less intense cavitation conditions. Absence of the release of cytoplasmic enzymes to a significant extent, absence of micronisation as observed by TEM and presence of a lower number of proteins bands in the culture supernatant on SDS-PAGE analysis following hydrodynamic cavitation compared to disruption by high-pressure homogenisation confirmed the selective release offered by hydrodynamic cavitation.
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PMID:Disruption of Brewers' yeast by hydrodynamic cavitation: Process variables and their influence on selective release. 1657 Mar 16

Azasugars, "nitrogen in the ring" analogues of monosaccharides, are known to be distributed in select plant, fungal. and bacterial species. We identify Chitinophaga pinensis DSM 2588 as the first bacterial source of the plant pyrrolidine azasugar 1,4-dideoxy-1,4-aminoarabinitol (DAB-1). Comparative sequence analyses identified C. pinensis as a putative azasugar producer, via observation of a three-gene cluster coding for putative aminotransferase, alcohol dehydrogenase, and sugar phosphatase enzymes, similar to the previously reported azasugar biosynthetic signature identified in Bacillus amyloliquefaciens FZB42. Multistep fractionation of C. pinensis culture media guided by a maltase inhibition assay yielded a component with a mass consistent with the structure of DAB-1. Heterologous expression of the three-gene cluster in E. coli, a non-azasugar producer, led to the isolation of nectrisine, a biosynthetic precursor to DAB-1, which displayed potent slow tight binding inhibition of maltase. Reduction of nectrisine with NaBH₄ removed the slow tight binding inhibition kinetics, and MS analysis provided evidence for the production of a compound matching that of the isolated DAB-1 from C. pinensis. ¹H NMR analysis of the nectrisine produced in E. coli after NaBD₄ reduction produced a spectrum consistent with DAB-1 deuterated at C-1, primarily at the pro-S position. These results support the idea that the azasugar three-gene cluster represents a general biosynthetic path leading to several different compounds, which may prove useful for the identification of other azasugar-producing organisms.
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PMID:Functional Analysis of a Gene Cluster from Chitinophaga pinensis Involved in Biosynthesis of the Pyrrolidine Azasugar DAB-1. 3179 83


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