Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.21 (beta-glucosidase)
 3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously isolated a phosphate starvation-response (psr) cDNA clone, psr3.1, from Brassica nigra which encodes a beta-glucosidase. Southern blots of Arabidopsis thaliana genomic DNA probed with the psr3.1 cDNA indicated that this gene exists as a single locus. A genomic library of A. thaliana was screened at high stringency to isolate the corresponding genomic clone. The resultant clone was coined psr3.2 because of its sequence divergence from isolated psr3.1 cDNA clones. Northern blotting with probes derived from the coding region of the genomic clone showed that this gene is expressed at high levels in P(i)-starved roots and the enhancement occurred within two days of growth in medium lacking P(i). The expression of this gene is repressed by heat shock and anaerobic conditions, and it is not significantly induced by high salinity, or by nitrogen or sulfur deprivation. Sequence analysis of the genomic clone revealed the existence of 13 exons interrupted by 12 AT-rich introns and it possessed a high homology with the B. nigra psr3.1 as well as various other beta-glucosidase genes from other species. Sequence similarity and divergence percentages between the deduced amino acid sequences of the psr3 clones and other beta-glycosidases suggests that they should be included along with two other Brassicaceae genes in a distinct subfamily of the BGA glycosidase gene family. The presence of an endoplasmic reticulum retention signal at the carboxy terminus indicates the likely cellular location of PSR3.2. The possible metabolic and regulatory roles of this enzyme during the P(i)-starvation response are discussed.
Plant Mol Biol 1997 May
PMID:A phosphate-starvation inducible beta-glucosidase gene (psr3.2) isolated from Arabidopsis thaliana is a member of a distinct subfamily of the BGA family. 917 12

This study describes the characterization of BpH3, a Bordetella pertussis DNA-binding protein. Sequence analysis reveals significant homology with the H-NS sequence of Escherichia coli and Haemophilus influenzae, particularly in the C-terminal part of the proteins. Our results provide evidence that H-NS and BpH3 display functional homology. First, expression of BpH3 in an hns mutant results in restoration of motility, an H-NS-dependent phenotype. This effect is dependent on the level of BpH3 expression and results from transcriptional activation of the flagellar master operon. Second, the high level of beta-glucosidase associated with hns mutations is reversed to the low wild-type level in the presence of BpH3. Third, BpH3 is able, like H-NS, to preferentially bind in vitro to curved DNA fragments, such as flhDC and bla promoter regions. Our results are the first demonstration that proteins homologous to H-NS exist in bacteria phylogenetically distant from H. influenzae and enterobacteria.
Mol Microbiol 1997 May
PMID:Characterization of BpH3, an H-NS-like protein in Bordetella pertussis. 919 8

BT-R1, the Manduca sexta midgut receptor for the crystal toxin Cry1Ab produced by Bacillus thuringiensis ssp. berliner, was partly purified by gel filtration from M. sexta brush border membrane vesicles in the presence of the detergent CHAPS. Fractions containing BT-R1 were tested for their stability against degradation as indicated by retention of Cry1Ab binding on ligand blots. At 4 degrees C and pH 7.4 in the presence of Ca2+, BT-R1 was stable for up to 48 h but a 65% loss of binding was observed after 100 h. Under the same conditions, no loss of binding was observed in the presence of EGTA after 100 h. Cry1Ab binding decreased markedly as pH increased from 6 to 10 for incubations of 24 h at 4 degrees C. Increasing the temperature of incubation from 4 to 37 degrees C also decreased Cry1Ab binding. Neither metal ions nor free sulfhydryl groups are involved in Cry1Ab binding to BT-R1. A trypsin-like, metal-ion-dependent proteolytic activity co-eluted with BT-R1 during gel filtration. This endoproteolytic activity was unaltered by the addition of Cry1Ab. BT-R1 did not co-elute with peaks of aminopeptidase, alkaline phosphatase, alpha-glucosidase, beta-glucosidase and beta-galactosidase activities. When BT-R1 in the gel filtration fraction was further purified on a Mono Q anion exchange column, partial separation of the trypsin-like activity from BT-R1 was observed. BT-R1 could be removed from the appropriate Mono Q fraction by immunoprecipitation with only a slight decrease in this activity. These results demonstrate that there is no copurification of BT-R1 and these enzymes and that BT-R1 is unlikely to form complexes with them. Binding of Cry1Aa and Cry1Ac to BT-R1 in gel filtration fractions is similar to that of Cry1Ab, indicating that BT-R1 may be the high-affinity receptor for the Cry1A toxins. Binding of Cry1Ab to a 120 kDa protein has not been observed in this study.
Insect Biochem Mol Biol 1997 Jun
PMID:Further characterization of BT-R1, the cadherin-like receptor for Cry1Ab toxin in tobacco hornworm (Manduca sexta) midguts. 930 95

A microplate assay, for use with a variety of glycohydrolase enzymes, was developed to aid the screening of Chinese medicinal herb extracts for the presence of potential anti-viral and anti-lymphoma compounds. The microplate assay method described offers greater convenience, speed and reproducibility over existing methods. The enzymes tested were alpha-glucosidase, beta-glucosidase and beta-glucuronidase. The assay can be easily adapted for use with other glycohydrolase enzymes. Of the 12 herb extracts examined four did not inhibit any of the enzymes (< 50% inhibition), one inhibited alpha-glucosidase only (> 50% inhibition), six inhibited beta-glucuronidase only, and one inhibited both alpha-glucosidase and beta-glucuronidase. None of the extracts were capable of inhibiting beta-glucosidase to any significant extent.
Biochem Mol Biol Int 1997 Sep
PMID:Inhibition of glycohydrolase enzymes by aqueous extracts of Chinese medicinal herbs in a microplate format. 930 34

The marine rotifer, Brachionus plicatilis, is able to digest Chlorella efficiently, suggesting that the rotifer contains a powerful cellulolytic enzyme system. A multi-component cellulolytic complex, including endoglucanase (CM-cellulase), cellobiohydrolase and beta-glucosidase, was found in Brachionus plicatilis. Endoglucanase (endo-beta-1,4 glucanase) was purified to homogeneity from rotifer homogenates using a sequential chromatographic method. The purified enzyme exhibits a strong hydrolytic activity with carboxymethyl(CM)-cellulose. The optimum temperature and pH for the endoglucanase activity were 37 degrees C and 7.0, respectively. 80% of the CM-cellulase activity was retained in salt mixture that ranged from 150 to 500 mM NaCl equivalent. The purified protein was isolated with a molecular weight of approximately 62 kDa estimated by SDS-polyacrylamide gel electrophoresis.
Biochem Mol Biol Int 1997 Oct
PMID:Purification and characterization of an endoglucanase from the marine rotifer, Brachionus plicatilis. 935 Mar 31

Relatively little is known about pollen development at the molecular level. For the purpose of gaining understanding of the molecular control of pollen development, a number of Arabidopsis cDNA fragments were isolated using subtractive hybridizations. DNA and RNA hybridizations and sequence analyses indicate that we have isolated cDNAs representing 13 genes. Sequences for 8 of these genes are novel, while those for the remaining 5 genes have substantial similarity to genes previously reported as anther- or pollen-specific. RNA in situ hybridizations with 5 genes revealed that four of them are tapetum-specific with differing temporal expression patterns during pollen development and one is pollen-specific within the flower. Sequence analysis of full-length cDNAs showed that one of the novel genes, ATA7, encodes a protein related to lipid transfer proteins. Another gene, ATA20, encodes a protein with novel repeat sequences and a glycine-rich domain that shares a predicted structure with a known cell wall protein. The full-length ATA27 cDNA encodes a protein similar to the BGL4 beta-glucosidase from Brassica napus. The ATA27 protein is predicted to have an ER retention signal and an acidic isoelectric point, suggesting that it may be localized to the ER lumen. This may be a means of compartmentalization from its substrate(s). Our studies demonstrate that subtractive hybridizations can be used to identify previously unknown genes, which should be valuable tools for further study of pollen and anther development and function.
Plant Mol Biol 1998 Jul
PMID:Identification, sequence analysis and expression studies of novel anther-specific genes of Arabidopsis thaliana. 968 65

To determine the number of proteins required for mating type (MAT) locus-regulated control of mating in Cochliobolus heterostrophus, MAT fragments of various sizes were expressed in MAT deletion strains. As little as 1.5 kb of MAT sequence, encoding a single unique protein in each mating type (MAT-1 and MAT-2), conferred mating ability, although an additional 160 bp of 3' UTR was needed for production of ascospores. No other mating type-specific genes involved in mating identity or fertility were found. Thus, although homologs of the C. heterostrophus MAT-1 and MAT-2 genes exist in the filamentous ascomycetes Neurospora crassa and Podospora anserina, C. heterostrophus does not appear to have mating type-specific homologs of two additional genes required by both N. crassa and P. anserina for successful sexual reproduction. Three genes were identified in the common DNA flanking the MAT locus: a gene encoding a GTPase-activating protein and an ORF of unknown function lie 5' while a beta-glucosidase encoding gene lies found 3'. None of these genes appears to be involving in the mating process.
Mol Gen Genet 1998 Aug
PMID:Single mating type-specific genes and their 3' UTRs control mating and fertility in Cochliobolus heterostrophus. 974 70

Phosphatases, C4 and C8 esterases, leucine and valine aminopeptidases, N-acetyl-beta-glucosaminidase, beta-glucosidase, beta-galactosidase and beta-glucuronidase were detected in extracts of the parasitic mite Psoroptes cuniculi. Lipase, trypsin-like and chymotrypsin-like activities were not present. Haemoglobin was hydrolysed by a detergent-soluble fraction of the mite extracts with a maximum hydrolysis between pH 3 and 5. Acid proteinase activity was greater against haemoglobin than bovine serum albumin. Inhibitors of cysteine, serine and metallo-proteinases failed to inhibit the hydrolysis of H-Pro-Thr-Glu-Phe-Phe(NO2)-Arg-Leu-OH while pepstatin A inhibited its hydrolysis in a dose-dependent manner (IC50 8.02 x 10(-11) M (+/- 0.30 x 10(-11). Thermal inactivation of the proteolytic activity followed an exponential decay pattern. Typical K(m) and Vmax values were 7.2 x 10(-5) (+/- 0.7 x 10(-5) M-1 and 1.13 x 10(-3) (+/- 0.05 x 10(-3) OD unit-1 min-1 respectively. Acid proteinase activity eluted from a size exclusion column in a single, major peak representing a molecular weight range of 21-24.5 kDa. The major endoproteinase of P. cuniculi therefore appears to be a cathepsin D-like aspartic proteinase.
Insect Biochem Mol Biol 1999 Jan
PMID:Hydrolytic enzymes of Psoroptes cuniculi (Delafond). 1007 Jul 42

Coniferin beta-glucosidase (CBG) catalyzes the hydrolysis of monolignol glucosides to release the cinnamyl alcohols for oxidative polymerization to lignin. Utilizing the N-terminal amino acid sequence of the purified enzyme, the corresponding full-length cDNA sequence was isolated from a Pinus contorta xylem-specific library. The isolated 1909 nucleotide cDNA was confirmed to be that of CBG on the basis of its high homology to family 1 glycosyl hydrolases, the sequence identity with the N-terminal amino acid residues of the purified enzyme, and the coniferin hydrolytic activity and substrate specificity profile displayed by the recombinant protein when expressed in Escherichia coli. The presence of a 23 amino acid N-terminal signal peptide in the deduced 513 amino acid enzyme suggests that CBG is a secretory protein targeted to the ER. The isolation of CBG cDNA will facilitate the evaluation of the importance of this enzyme in the ultimate stages of lignin biosynthesis and could be a valuable tool in manipulating lignin levels in xylem cell walls.
Plant Mol Biol 1999 May
PMID:cDNA cloning and heterologous expression of coniferin beta-glucosidase. 1041 14

An alpha-L-rhamnosidase clone was isolated from a genomic library of the thermophilic anaerobic bacterium Clostridium stercorarium and its primary structure was determined. The recombinant gene product, RamA, was expressed in Escherichia coli, purified to homogeneity and characterized. It is a dimer of two identical subunits with a monomeric molecular mass of 95 kDa in SDS polyacrylamide gel electrophoresis. At pH 7.5 it is optimally active at 60 degrees C and insensitive to moderate concentrations of Triton X100, ethanol and EDTA. It hydrolysed p-nitrophenyl-alpha-L-rhamnopyranoside, naringin and hesperidin with a specific activity of 82, 1.5 and 0.46 U mg-1 respectively. Hydrolysis occurs by inversion of the anomeric configuration as detected using 1H-NMR, indicating a single displacement mechanism. Naringin was hydrolysed to rhamnose and prunin, which could further be degraded by incubation with a thermostable beta-glucosidase. The secondary structure of RamA consists of 27% alpha-helices and 50% beta-sheets, as detected by circular dichroism. The primary structure of the ramA gene has no similarity to other glycoside hydrolase sequences and possibly is the first member of a new enzyme family.
Mol Microbiol 2000 Jan
PMID:The thermostable alpha-L-rhamnosidase RamA of Clostridium stercorarium: biochemical characterization and primary structure of a bacterial alpha-L-rhamnoside hydrolase, a new type of inverting glycoside hydrolase. 1063 87


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