Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Interaction of soluble glucosyl- and mannosyl-transferase enzyme activities in the synthesis of a glucomannan.

ABSTRACT: A neutral-detergent-solubilized-enzyme preparation derived from Phaseolus aureus hypocotyls contains two types of glycosyltransferase activity. One, mannosyltransferase enzyme activity, utilizes GDP-alpha-d-mannose as the sugar nucleotide substrate. The other, glucosyltransferase enzyme activity, utilizes GDP-alpha-d-glucose as the sugar nucleotide substrate. The soluble enzyme preparation catalyses the formation of what appears to be a homopolysaccharide when either sugar nucleotide is the only substrate present. A beta-(1-->4)-linked mannan is the only polymeric product when only GDP-alpha-d-mannose is added. A beta-(1-->4)-linked glucan is the only polymeric product when only GDP-alpha-d-glucose is added. In the presence of both sugar nucleotides, however, a beta-(1-->4)-linked glucomannan is formed. There are indications that endogenous sugar donors may be present in the enzyme preparation. There appear to be only two glycosyltransferases in the enzyme preparation, each catalysing the transfer of a different sugar to the same type of acceptor molecule. The glucosyltransferase requires the continual production of mannose-containing acceptor molecules for maintenance of enzyme activity, and is thereby dependent upon the activity of the mannosyltransferase. The mannosyltransferase, on the other hand, does not require the continual production of glucose-containing acceptors for maintenance of enzyme activity, but is severely inhibited by GDP-alpha-P-glucose. These properties promote the synthesis of beta-(1-->4)-linked glucomannan rather than beta-(1-->4)-linked glucan plus beta-(1-->4)-linked mannan when both sugar nucleotide substrates are present.

SUBMITTER: Heller JS

PROVIDER: S-EPMC1174166 | biostudies-other | 1972 Sep

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

A New Class of Glucosyl Thioureas: Synthesis and Larvicidal Activities.

Project description:A novel series of glucosyl thioureas were synthesized in good overall yields (up to 37% over four steps) from d-glucose and primary amines, and their larvicidal activities toward Mythimna separata Walker were also investigated. This new class of glucosyl thioureas demonstrated low to moderate growth inhibition activity of Mythiman separata Walker, with a growth inhibitory rate of up to 47.5% at a concentration of 100.0 mg/L in acetone.

| S-EPMC6274248 | biostudies-literature

Enzyme activities and subcellular localization of members of the Arabidopsis glutathione transferase superfamily.

Project description:Enzyme screens with Strep-tagged recombinant proteins and expression studies with the respective green fluorescent protein (GFP) fusions have been employed to examine the functional activities and subcellular localization of members of the Arabidopsis glutathione transferase (GST) superfamily. Fifty-one of 54 GST family members were transcribed and 41 found to express as functional glutathione-dependent enzymes in Escherichia coli. Functional redundancy was observed and in particular three theta (T) class GSTs showed conserved activities as hydroperoxide-reducing glutathione peroxidases (GPOXs). When expressed in tobacco as GFP fusions, all three GSTTs localized to the peroxisome, where their GPOX activity could prevent membrane damage arising from fatty acid oxidation. Through alternative splicing, two of these GSTTs form fusions with Myb transcription factor-like domains. Examination of one of these variants showed discrete localization within the nucleus, possibly serving a role in reducing nucleic acid hydroperoxides or in signalling. Based on this unexpected differential sub-cellular localization, 15 other GST family members were expressed as GFP fusions in tobacco. Most accumulated in the cytosol, but GSTU12 localized to the nucleus, a family member resembling a bacterial tetrachlorohydroquinone dehalogenase selectively associated with the plasma membrane, and a lambda GSTL2 was partially directed to the peroxisome after removal of a putative chloroplast transit peptide. Based on the results obtained with the GSTTs, it was concluded that these proteins can exert identical protective functions in differing subcellular compartments.

| S-EPMC2657551 | biostudies-literature

Facile Chemoenzymatic Synthesis of O-Mannosyl Glycans.

Project description:O?Mannosylation is a vital protein modification involved in brain and muscle development whereas the biological relevance of O-mannosyl glycans has remained largely unknown owing to the lack of structurally defined glycoforms. An efficient scaffold synthesis/enzymatic extension (SSEE) strategy was developed to prepare such structures by combining gram-scale convergent chemical syntheses of three scaffolds and strictly controlled sequential enzymatic extension catalyzed by glycosyltransferases. In total, 45 O-mannosyl glycans were obtained, covering the majority of identified mammalian structures. Subsequent glycan microarray analysis revealed fine specificities of glycan-binding proteins and specific antisera.

| S-EPMC6097902 | biostudies-literature

Identification of glucosyl transferase inhibitors from Psidium guajava against Streptococcus mutans in dental caries.

Project description:Dental caries is a multi factorial disease that starts with microbiological shifts affected by salivary flow, composition, exposure to fluoride, consumption of dietary sugars, and preventive behaviours. The Streptococcus mutans (S. mutans) is an initiator of caries because there is a variety of a virulence factor unique to the bacterium that has been isolated and plays an important role in caries formation. The aim of the present study is to identify the beneficial effect of bioactive compounds in Psidium guajava (P. guajava) and its inhibitory role against S. mutans in dental caries. The methanolic extract was used for analysis of GC-MS for the identification of bioactive compounds. The results confirm the existence of 7 different compounds. The identified bioactive compounds were corynan-17-ol, 18,19-didehydro-10-methyoxy-acetate, Copaene, 3Bicyclo(5.2.0)nonane, 2-methylene-4,8,8-trimethyl-4-vinyl,Azulene,1,2,3a,4,5,6,7-octahydro-1,4-dimethyl-7-methylethenyl) [1R- (1a,3aa',4a',7a')], ?-Caryophyllene, Alloaromadendrene oxide-(1) and Androstan-17-one, 3-ethyl-3-hydroxy-, (5a). The saliva of dental caries during and after treatment of aqueous leaf extract was used for the analysis of bacterial load and determining the activity of Glucosyl transferase (GTF). The result obtained at different time intervals, showed significant decrease (P < 0.01) in the bacterial load of saliva on P. guajava treatment. The molecular docking studies identified the interaction between GTF and the bioactive compounds of P. guajava. The anticariogenic active compounds interacted through active sites of sucrose and inhibit the formation of glucan. The study suggested that it could be maximized the anticariogenic effect of the selected medicinal plant, and further focus is needed to identify the combined plant extract to explore the additional protection against dental caries.

| S-EPMC6435953 | biostudies-literature

Molecular analysis of CaMnt1p, a mannosyl transferase important for adhesion and virulence of Candida albicans.

Project description:There is an immediate need for identification of new antifungal targets in opportunistic pathogenic fungi like Candida albicans. In the past, efforts have focused on synthesis of chitin and glucan, which confer mechanical strength and rigidity upon the cell wall. This paper describes the molecular analysis of CaMNT1, a gene involved in synthesis of mannoproteins, the third major class of macromolecule found in the cell wall. CaMNT1 encodes an alpha-1, 2-mannosyl transferase, which adds the second mannose residue in a tri-mannose oligosaccharide structure which represents O-linked mannan in C. albicans. The deduced amino acid sequence suggests that CaMnt1p is a type II membrane protein residing in a medial Golgi compartment. The absence of CaMnt1p reduced the ability of C. albicans cells to adhere to each other, to human buccal epithelial cells, and to rat vaginal epithelial cells. Both heterozygous and homozygous Camnt1 null mutants of C. albicans showed strong attenuation of virulence in guinea pig and mouse models of systemic candidosis, which, in guinea pigs, could be attributed to a decreased ability to reach and/or adhere internal organs. Therefore, correct CaMnt1p-mediated O-linked mannosylation of proteins is critical for adhesion and virulence of C. albicans.

| S-EPMC22718 | biostudies-literature

Alanine-scanning mutagenesis of protein mannosyl-transferase from Streptomyces coelicolor reveals strong activity-stability correlation.

Project description:In Actinobacteria, protein O-mannosyl transferase (Pmt)-mediated protein O-glycosylation has an important role in cell envelope physiology. In S. coelicolor, defective Pmt leads to increased susceptibility to cell wall-targeting antibiotics, including vancomycin and β-lactams, and resistance to phage ϕC31. The aim of this study was to gain a deeper understanding of the structure and function of S. coelicolor Pmt. Sequence alignments and structural bioinformatics were used to identify target sites for an alanine-scanning mutagenesis study. Mutant alleles were introduced into pmt-deficient S. coelicolor strains using an integrative plasmid and scored for their ability to complement phage resistance and antibiotic hypersusceptibility phenotypes. Twenty-three highly conserved Pmt residues were each substituted for alanine. Six mutant alleles failed to complement the pmt▬ strains in either assay. Mapping the six corresponding residues onto a homology model of the three-dimensional structure of Pmt, indicated that five are positioned close to the predicted catalytic DE motif. Further mutagenesis to produce more conservative substitutions at these six residues produced Pmts that invariably failed to complement the DT1025 pmt▬ strain, indicating that strict residue conservation was necessary to preserve function. Cell fractionation and Western blotting of strains with the non-complementing pmt alleles revealed undetectable levels of the enzyme in either the membrane fractions or whole cell lysates. Meanwhile for all of the strains that complemented the antibiotic hypersusceptibility and phage resistance phenotypes, Pmt was readily detected in the membrane fraction. These data indicate a tight correlation between the activity of Pmt and its stability or ability to localize to the membrane.

| S-EPMC8698208 | biostudies-literature

Synthesis of water-soluble dinuclear mn-porphyrin with multiple antioxidative activities.

Project description:Superoxide dismutase (SOD) and catalase activities of a drug are of great importance for its effective protection against reactive oxygen species (ROS)-induced injury. Achievement of catalase activity of a synthetic compound remains a challenge. Water-soluble Mn-porphyrins have high SOD and peroxynitrite (ONOO(-)) reducing activities, but not catalase-like activity. Herein, we are able to retain the fair SOD-like activity of a mononuclear Mn-5-(N-methylpyridinium-4-yl)-10,15,20-triphenyl porphyrin (MnM4PyP3P), while gaining in catalase-like activity with its dinuclear complex, 1,3-di[5-(N-methylene-pyridinium-4-yl)-10,15,20-triphenyl porphynato manganese] benzene tetrachloride (MnPD). Mechanistic study indicates that catalase-like activity of MnPD is due to synergism of two Mn active sites, where hydroxo-Mn(IV) complex is formed as an intermediate. The in vivo experiments demonstrate that MnPD significantly restores the treadmill-running ability of SOD-deficient mouse and thus indicates the therapeutic potential of MnPD. Furthermore, MnPD may serve as a mechanistic tool and indicate the new directions in the synthesis of catalase-like mimics.

| S-EPMC4060938 | biostudies-literature

Identification of the gene (lgtG) encoding the lipooligosaccharide beta chain synthesizing glucosyl transferase from Neisseria gonorrhoeae.

Project description:The lipooligosaccharide from Neisseria gonorrhoeae (GC), consists of lipid A, an oligosaccharide core and three branches, alpha, beta, and gamma. We report the cloning of the gene (lgtG, lipooligosaccharide glycosyl transferase G) encoding the glucosyl transferase of GC that initiates the beta chain which consists of a lactosyl moiety. This gene contains a homopolymeric tract of cytidine [poly(C)] and we demonstrate that changes in the number of Cs in poly(C) account for the variation of beta chain expression in different GC strains. Biochemical analyses and mass spectrometry clearly attribute the reactivity of mAb 2C7 to the presence of the lactosyl beta chain. In addition, we demonstrate that in the absence of the lactosyl group, a phosphoethanolamine is added to generate a new antigenic epitope as evidenced by the gain of reactivity to mAb 2-L1-8. These results show that, like the alpha chain, the beta chain of lipooligosaccharide is subject to antigenic variation.

| S-EPMC27988 | biostudies-literature

Synthesis and anti-cancer activities of a water soluble gold(III) porphyrin.

Project description:Gold(III) compounds continue to be explored for their potential utility as anticancer agents. A recognized limitation is the reactivity of gold(III), which is typically reduced to the more labile gold(I) state under physiological conditions. The use of porphyrins can overcome this problem. However, to date the stabilization provided by the use a strongly chelating porphyrin is offset by the poor solubility of the resulting complex in aqueous media. In this work, we describe the synthesis and in vitro anti-cancer activity of a gold(III)porphyrin complex with relatively good aqueous solubility. As judged from standard antiproliferation assays, this complex displays an IC50 of 9 μM for the A2780 human ovarian cancer cell line. This is a higher level of potency than displayed by two related control systems.

| S-EPMC4407279 | biostudies-literature

Mimivirus encodes a multifunctional primase with DNA/RNA polymerase, terminal transferase and translesion synthesis activities.

Project description:Acanthamoeba polyphaga mimivirus is an amoeba-infecting giant virus with over 1000 genes including several involved in DNA replication and repair. Here, we report the biochemical characterization of gene product 577 (gp577), a hypothetical protein (product of L537 gene) encoded by mimivirus. Sequence analysis and phylogeny suggested gp577 to be a primase-polymerase (PrimPol)-the first PrimPol to be identified in a nucleocytoplasmic large DNA virus (NCLDV). Recombinant gp577 protein purified as a homodimer and exhibited de novo RNA as well as DNA synthesis on circular and linear single-stranded DNA templates. Further, gp577 extends a DNA/RNA primer annealed to a DNA or RNA template using deoxyribonucleoties (dNTPs) or ribonucleotides (NTPs) demonstrating its DNA/RNA polymerase and reverse transcriptase activity. We also show that gp577 possesses terminal transferase activity and is capable of extending ssDNA and dsDNA with NTPs and dNTPs. Mutation of the conserved primase motif residues of gp577 resulted in the loss of primase, polymerase, reverse transcriptase and terminal transferase activities. Additionally, we show that gp577 possesses translesion synthesis (TLS) activity. Mimiviral gp577 represents the first protein from an NCLDV endowed with primase, polymerase, reverse transcriptase, terminal transferase and TLS activities.

| S-EPMC6648351 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data