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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The RNA polymerase inhibitor, lomofungin has been used to determine the half life of specific synthetic capacities (invertase and
alpha-glucosidase
) as well as that for gross protein synthesis. In both cases the studies conclude that cognate messenger RNAs decay with a half life of approximately 20 minutes. This antibiotic has been used to determine the half life of allophanate hydrolase specific synthetic capacity. We find that it decays with a half life of about three minutes; a value that agrees with the decay rates of allophanate hydrolase synthetic capacity following removal of inducer. These observations argue that mRNA may be metabolized by two separate routes in Saccharomyces.
Mol
Gen Genet 1975
PMID:Lomofungin inhibition of allophanate hydrolase synthesis in Saccharomyces cerevisiae. 110 15
Saccharomyces strains capable of fermenting maltose contain any one of five telomere-associated MAL loci. Each MAL locus is a complex of three genes encoding the three functions required to ferment maltose: maltose permease (GENE 1),
maltase
(GENE 2) and the MAL trans-activator (GENE 3). All five loci have been cloned and all are highly sequence homologous over at least a 9.0 kbp region containing these GENEs (Charron et al., Genetics 122, 307-331, 1989). Our initial studies of strains carrying the MAL3 locus indicated the presence of linked, repeated MAL-homologous sequences (Michels and Needleman,
Mol
. Gen. Genet. 191, 225-230, 1983). Here we report our analysis of the centromere-proximal MAL3-linked sequences and show that the complete MAL3 locus spans approximately 40 kbp and consists of tandemly arrayed, partial repeats of the three GENE sequences described above. In addition, the structure of the MAL3 locus is compared to that of three partially functional alleles of MAL3. These alleles were shown to contain only MAL31 and MAL32 and their structure suggests that they resulted from MAL3 deletions removing the sequences centromere-proximal to MAL31. The amplification and rearrangement of the telomere-linked MAL3 sequences are discussed in the context of studies on other telemere-associated sequences from yeast and other species.
...
PMID:The telomere-associated MAL3 locus of Saccharomyces is a tandem array of repeated genes. 144 45
Lec23 Chinese hamster ovary (CHO) cells have been shown to possess a unique lectin resistance phenotype and genotype compared with previously isolated CHO glycosylation mutants (Stanley, P., Sallustio, S., Krag, S. S., and Dunn, B. (1990) Somatic Cell
Mol
. Genet. 16, 211-223). In this paper, a biochemical basis for the lec23 mutation is identified. The carbohydrates associated with the G glycoprotein of vesicular stomatitis virus (VSV) grown in Lec23 cells (Lec23/VSV) were found to possess predominantly oligomannosyl carbohydrates that bound strongly to concanavalin A-Sepharose, eluted 3 sugar eq beyond a Man9GlcNAc marker oligosaccharide on ion suppression high pressure liquid chromatography, and were susceptible to digestion with jack bean alpha-mannosidase. Monosaccharide analyses revealed that the oligomannosyl carbohydrates contained glucose, indicating a defect in
alpha-glucosidase
activity. This was confirmed by further structural characterization of the Lec23/VSV oligomannosyl carbohydrates using purified rat mammary gland
alpha-glucosidase
I, jack bean alpha-mannosidase, and 1H NMR spectroscopy at 500 MHz. [3H]Glucose-labeled Glc3Man9GlcNAc was prepared from CHO/VSV labeled with [3H]galactose in the presence of the processing inhibitors castanospermine and deoxymannojirimycin. Subsequently, [3H]Glc2Man9GlcNAc was prepared by purified
alpha-glucosidase
I digestion of [3H]Glc3Man9GlcNAc. When these oligosaccharides were used as
alpha-glucosidase
substrates it was revealed that Lec23 cells are specifically defective in
alpha-glucosidase
I, a deficiency not previously identified among mammalian cell glycosylation mutants.
...
PMID:A novel glycosylation phenotype expressed by Lec23, a Chinese hamster ovary mutant deficient in alpha-glucosidase I. 166 Apr 60
Maltose fermentation in Saccharomyces species requires the presence of at least one of five unlinked MAL loci: MAL1, MAL2, MAL3, MAL4 and MAL6. Each MAL locus is complex consisting of at least three genes: a trans-acting activator, a maltose permease, and
maltase
. All the MAL loci show homology to each other both at the sequence level as determined by Southern transfer analysis and at the functional level as determined by complementation. We describe the organization of the MAL loci in yeast and the basic features of their regulation. The analysis of MAL has contributed to our understanding of the evolution of multigenic families, the global integration of carbohydrate metabolism, and gene regulation.
Mol
Microbiol 1991 Sep
PMID:Control of maltase synthesis in yeast. 176 81
Acemannan (ACE-M), a beta-(1,4)-linked acetylated mannan, was evaluated for in vitro activity against human immunodeficiency virus type 1 (HIV-1). Castanospermine (CAS), deoxymannojirimycin (DMN), swainsonine (SWS), azidothymidine (AZT), and dideoxythymidine (DDC) were tested in parallel as control compounds. In vitro antiviral efficacy of ACE-M was evaluated in a variety of cell lines including human peripheral mononuclear, CEM-SS1 and MT-2(2) cells. The virus strain, number of infectious units per cell, and target cell line were important factors in determining the degree of inhibition of viral cytopathic effect in the presence of ACE-M and other control compounds tested. Maximum inhibitory effect was observed in CEM-SS cells infected with the RFII strain of HIV-1. This inhibitory effect was determined to be concentration-dependent. Assay design included primary screening to measure cell viabilities of infected target cells in the presence and absence of test compounds. When tested on HIV-1/RFII-infected CEM-SS cells, the 50% inhibitory effect of CAS (IC50 = 28), an inhibitor of
alpha-glucosidase
I, was determined to be similar to that observed for ACE-M (IC50 = 45). However, DMN and SWS, inhibitors of mannosidase I and II, tested in parallel to CAS and ACE-M, exhibited no IC50 values. Antiviral potential of ACE-M as an inhibitor of syncytia formation was also explored using CEM-SS cells. Suppression of syncytia formation was observed at an ACE-M concentration of 31.25 micrograms/ml, and complete inhibition was observed at 62.5 micrograms/ml. In addition, HIV-1 RNA levels were studied to establish the antiviral potential of ACE-M in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol
Biother 1991 Sep
PMID:Inhibition of AIDS virus replication by acemannan in vitro. 176 65
Various aspects of lysosome biogenesis have been studied in Chinese hamster ovary (CHO) cells of the End3 complementation group (designated G.7.1 cells), which display a temperature-sensitive defect in the acidification of endosomes, but not lysosomes. In G.7.1 and normal wild-type cells grown at the permissive temperature (34 degrees C), the lysosomal enzymes
alpha-glucosidase
and cathepsin D were synthesized as high-molecular-weight precursors that subsequently underwent intracellular proteolytic processing to yield lower molecular weight mature forms. The mature forms of the enzymes were retained in cells, and small amounts of each precursor were secreted. However, in G.7.1 cells grown at the restrictive temperature (41 degrees C), there was a massive and inappropriate oversecretion of lysosomal enzyme precursors, which resulted in very little of the mature forms being processed and retained by the cells. This mistargeting of lysosomal enzymes was not due to an absence of phosphorylated oligosaccharides on the enzymes, nor to a defect in mannose 6-phosphate (Man6P) receptors. However, it was found that whereas G.7.1 cells had the same number of cell surface Man6P receptors at 34 degrees C and 41 degrees C, the rate of accumulation and degradation of Man6P-containing ligands was about two to three times more rapid in cells maintained at the permissive temperature. There did not appear to be any gross changes in Golgi function as the oligosaccharides of
alpha-glucosidase
and the Man6P receptor were processed in a similar fashion at both 34 degrees C and 41 degrees C. In addition to these studies, electron microscopic observations revealed that at 41 degrees C, G.7.1 cells accumulated inclusion-type bodies reminiscent of those found in I-cell disease fibroblasts. Thus, the biochemical and electron microscopic results on G.7.1 cells provide further evidence that acidified endosomes are important for the biogenesis of lysosomes.
Somat Cell
Mol
Genet 1991 Mar
PMID:Biosynthesis of lysosomal enzymes in cells of the End3 complementation group conditionally defective in endosomal acidification. 184 19
Maltose fermentation in Saccharomyces species requires the presence of at least one of five unlinked MAL loci: MAL1, MAL2, MAL3, MAL4, and MAL6. Each of these loci consists of a complex of genes involved in maltose metabolism; the complex includes
maltase
, a maltose permease, and an activator of these genes. At the MAL6 locus, the activator is encoded by the MAL63 gene. While the MAL6 locus has been the subject of numerous studies, the binding sites of the MAL63 activator have not been determined. In this study, we used Escherichia coli extracts containing the MAL63 protein to define the binding sites of the MAL63 protein in the divergently transcribed MAL61-62 promotor. When a DNA fragment containing these sites was placed upstream of a CYC1-lacZ gene, maltose induced beta-galactosidase. These sites therefore constitute an upstream activating sequence for the MAL genes.
Mol
Cell Biol 1990 Jul
PMID:Identification of the upstream activating sequence of MAL and the binding sites for the MAL63 activator of Saccharomyces cerevisiae. 219 62
Predictions of protein secondary structure are used with amino acid sequence alignments to show that the N-terminal domains of cyclodextrin glucanotransferases and a yeast
alpha-glucosidase
may have the same super-secondary structure as alpha-amylases, i.e. an (alpha/beta)8-barrel fold. Sequence similarities provide evidence that glucanotransferases, and possibly the glucosidase, are, like alpha-amylases, Ca2+-containing enzymes. The relationship between substrate specificity and the nature of the amino acid residues proposed at the active site is discussed for the transferases and
alpha-glucosidase
. A set of three programs for an Apple IIe computer to carry out the calculations described by Garnier, Osguthorpe & Robson [(1978) J.
Mol
. Biol. 120, 97-120] and a set of four programs for an Apple IIe computer to carry out the calculations described by Levin, Robson & Garnier [(1986) FEBS Lett. 205, 303-308] have been deposited as Supplementary Publication SUP 50149 (25 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1989) 257, 5.
...
PMID:A super-secondary structure predicted to be common to several alpha-1,4-D-glucan-cleaving enzymes. 252 86
Starch-degrading, amylolytic enzymes are widely distributed among microbes. Several activities are required to hydrolyze starch to its glucose units. These enzymes include alpha-amylase, beta-amylase, glucoamylase,
alpha-glucosidase
, pullulan-degrading enzymes, exoacting enzymes yielding alpha-type endproducts, and cyclodextrin glycosyltransferase. Properties of these enzymes vary and are somewhat linked to the environmental circumstances of the producing organisms. Features of the enzymes, their action patterns, physicochemical properties, occurrence, genetics, and results obtained from cloning of the genes are described. Among all the amylolytic enzymes, the genetics of alpha-amylase in Bacillus subtilis are best known. Alpha-Amylase production in B. subtilis is regulated by several genetic elements, many of which have synergistic effects. Genes encoding enzymes from all the amylolytic enzyme groups dealt with here have been cloned, and the sequences have been found to contain some highly conserved regions thought to be essential for their action and/or structure. Glucoamylase appears usually in several forms, which seem to be the results of a variety of mechanisms, including heterogeneous glycosylation, limited proteolysis, multiple modes of mRNA splicing, and the presence of several structural genes.
Crit Rev Biochem
Mol
Biol 1989
PMID:Microbial amylolytic enzymes. 254 11
Multigene families are a ubiquitous feature of eukaryotes; however, their presence in Saccharomyces is more limited. The MAL multigene family is comprised of five unlinked loci, MAL1, MAL2, MAL3, MAL4 and MAL6, any one of which is sufficient for yeast to metabolize maltose. A cloned MAL6 locus was used as a probe to facilitate the cloning of the other four functional loci as well as two partially active alleles of MAL1. Each locus could be characterized as a cluster of three genes, MALR (regulatory), MALT (maltose transport or permease) and MALS (structural or
maltase
), encoded by a total of about 7 kb of DNA; however, homologous sequences at each locus extend beyond the coding regions. Our results indicate that there is extensive homology among the MAL loci, especially within their
maltase
genes. The greatest sequence diversity occurs in their regulatory gene regions. Southern cross analyses of the cloned MAL loci indicate a single duplication of the MAL6R-homologous sequences upstream of the MAL6R gene as well as an extensive duplication of more than 10 kb at the MAL3 locus. The large repeat at the MAL3 locus results in the presence of four copies of MAL3R-homologous sequences and two copies of MAL3T-homologous sequences at that locus. Two naturally occurring inactive alleles of MAL1 show a deletion or divergence of their MALR sequences. The significance of these repeats in the evolution of the MAL multigene family is discussed.
Mol
Gen Genet 1989 May
PMID:Structure of the multigene family of MAL loci in Saccharomyces. 254 70
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