scholarly journals Purification of the mammalian NgBR/hCITcis-prenyltransferase complex: Identification of a conserved carboxyterminal RxG motif crucial for enzymatic activity

2017 ◽  
Author(s):  
Kariona A. Grabińska ◽  
Ban H. Edani ◽  
Eon Joo Park ◽  
Jan R. Kraehling ◽  
William C. Sessa
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Substrate Binding ◽  
Large Family ◽  
Protein Glycosylation ◽  
Dolichyl Phosphate ◽  
Bacterial Enzyme ◽  
Purification System ◽  
Domains Of Life

SummaryCis-Prenyltransferases (cisPTs) constitute a large family of enzymes conserved during evolution and present in all domains of life. In eukaryotes and archaea,cisPT is the first enzyme committed to the synthesis of dolichyl-phosphate (DolP). DolP is obligate lipid carrier in protein glycosylation reactions in mammals. The homodimeric bacterial enzyme, undecaprenyl diphosphate synthase (UPPS) generates 11 isoprene units and has been structurally and mechanistically characterized in great detail. Recently our group discovered that unlike UPPS, mammaliancisPT is a heteromer consisting of NgBR (NUS1) and hCIT (DHDDS) subunits and this composition has been confirmed in plants and fungalcisPTs. Here, we establish the first purification system for heteromericcisPT and show that both NgBR and hCIT subunits function in catalysis and substrate binding. Finally, we identified a critical RxG sequence in the C-terminal tail of NgBR that is conserved and essential for enzyme activity across phyla.

scholarly journals The Hitchhiker's guide to glycoproteomics

2021 ◽  
Author(s):  
Tiago Oliveira ◽  
Morten Thaysen-Andersen ◽  
Nicolle H. Packer ◽  
Daniel Kolarich
Keyword(s):  
Functional Analysis ◽  
Cell Function ◽  
Prognostic Biomarker ◽  
Protein Glycosylation ◽  
Life Changes ◽  
Carrier Proteins ◽  
Post Translational Modifications ◽  
Starting Point ◽  
Domains Of Life ◽  
The Common

Protein glycosylation is one of the most common post-translational modifications that are essential for cell function across all domains of life. Changes in glycosylation are considered a hallmark of many diseases, thus making glycoproteins important diagnostic and prognostic biomarker candidates and therapeutic targets. Glycoproteomics, the study of glycans and their carrier proteins in a system-wide context, is becoming a powerful tool in glycobiology that enables the functional analysis of protein glycosylation. This ‘Hitchhiker's guide to glycoproteomics’ is intended as a starting point for anyone who wants to explore the emerging world of glycoproteomics. The review moves from the techniques that have been developed for the characterisation of single glycoproteins to technologies that may be used for a successful complex glycoproteome characterisation. Examples of the variety of approaches, methodologies, and technologies currently used in the field are given. This review introduces the common strategies to capture glycoprotein-specific and system-wide glycoproteome data from tissues, body fluids, or cells, and a perspective on how integration into a multi-omics workflow enables a deep identification and characterisation of glycoproteins — a class of biomolecules essential in regulating cell function.

scholarly journals GENETIC EVIDENCE FOR INTERACTION BETWEEN NONHOMOLOGOUS PROTEINS IN YEAST AND A CASE OF SUPPRESSION AT THE HIS1 LOCUS

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 327-339 ◽  
Author(s):  
Richard Snow
Keyword(s):  
Enzyme Activity ◽  
Low Temperature ◽  
Enzymatic Activity ◽  
Temperature Effect ◽  
Conformational Change ◽  
Minimal Medium ◽  
Genetic Evidence ◽  
Structural Genes ◽  
Wild Type ◽  
Is Strain

ABSTRACT The HIS1 and THR4 loci are the structural genes for phosphoribosyl-ATP pyrophosphorylase and threonine synthetase, respectively. The allele his1-IS has no enzyme activity at 30", but does have activity at 15" provided the cell contains the wild-type THR4 allele or a suppressing allele at another locus, designated SUP(his1-1S). Under these conditions, cells with the hisl-IS mutation are capable of growth on minimal medium at 15". Three kinds of reversions of a hisl-IS thr4 sup(his1-IS) strain to histidine prototrophy have been obtained: (1) his1-IS locus reversions to HIS1 that restore growth without added histidine at 30", (2)  thr4 reversions to THR4 that simultaneously eliminate the requirement for threonine and restore the low-temperature effect on the his1-IS allele, and (3)mutations from sup to SUP. The SUP allele is not an ochre suppressor, and it is not linked to either HISI, THR4 or a centromere. It may represent a missense suppressor. I t is proposed that the effect ofTHR4 is caused by aggregation of the wild-type threonine synthetase with defective his1-IS monomers, causing a favorable conformational change in the histidine protein that restores limited enzymatic activity. This can be regarded as a case of complementation between nonhomologous proteins.

Metallo-oxidase Enzymes: Design of their Active Sites

2011 ◽  
Vol 64 (3) ◽  
pp. 231 ◽  
Author(s):  
Zhiguang Xiao ◽  
Anthony G. Wedd
Keyword(s):  
Metal Ions ◽  
Active Sites ◽  
Specific Binding ◽  
Large Family ◽  
Outer Sphere ◽  
Transition Metal Ions ◽  
Substrate Oxidation ◽  
Cellular Functions ◽  
Domains Of Life ◽  
Low Valent

Multi-copper oxidases are a large family of enzymes prevalent in all three domains of life. They couple the one-electron oxidation of substrate to the four-electron reduction of dioxygen to water and feature at least four Cu atoms, traditionally divided into three sites: T1, T2, and (binuclear) T3. The T1 site catalyzes substrate oxidation while a trinuclear cluster (comprising combined T2 and T3 centres) catalyzes the reduction of dioxygen. Substrate oxidation at the T1 Cu site occurs via an outer-sphere mechanism and consequently substrate specificities are determined primarily by the nature of a substrate docking/oxidation (SDO) site associated with the T1 Cu centre. Many of these enzymes ‘moonlight’, i.e. display broad specificities towards many different substrates and may have multiple cellular functions. A sub-set are robust catalysts for the oxidation of low-valent transition metal ions such as FeII, CuI, and MnII and are termed ‘metallo-oxidases’. They play essential roles in nutrient metal uptake and homeostasis, with the ferroxidase ceruloplasmin being a prominent member. Their SDO sites are tailored to facilitate specific binding and facile oxidation of these low-valent metal ions and this is the focus of this review.

Hot and sweet: protein glycosylation in Crenarchaeota

2013 ◽  
Vol 41 (1) ◽  
pp. 384-392 ◽  
Author(s):  
Benjamin H. Meyer ◽  
Sonja-Verena Albers
Keyword(s):  
Living Cell ◽  
Protein Glycosylation ◽  
Haloferax Volcanii ◽  
Present Review ◽  
Sulfolobus Acidocaldarius ◽  
Glycosylphosphatidylinositol Anchor ◽  
Sweet Protein ◽  
Domains Of Life ◽  
Glycosylation Pathway ◽  
Sugar Chains

Every living cell is covered with a dense and complex array of covalently attached sugars or sugar chains. The majority of these glycans are linked to proteins via the so-called glycosylation process. Protein glycosylation is found in all three domains of life: Eukarya, Bacteria and Archaea. However, on the basis of the limit in analytic tools for glycobiology and genetics in Archaea, only in the last few years has research on archaeal glycosylation pathways started mainly in the Euryarchaeota Haloferax volcanii, Methanocaldococcus maripaludis and Methanococcus voltae. Recently, major steps of the crenarchaeal glycosylation process of the thermoacidophilic archaeon Sulfolobus acidocaldarius have been described. The present review summarizes the proposed N-glycosylation pathway of S. acidocaldarius, describing the phenotypes of the mutants disrupted in N-glycan biosynthesis as well as giving insights into the archaeal O-linked and glycosylphosphatidylinositol anchor glycosylation process.

Self-assembled nano-aggregates of fluorinases demonstrate enhanced enzymatic activity, thermostability and reusability

2020 ◽  
Vol 8 (2) ◽  
pp. 648-656
Author(s):  
Chunhao Tu ◽  
Jin Zhou ◽  
Lei Peng ◽  
Shuli Man ◽  
Long Ma
Keyword(s):  
Aqueous Solution ◽  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Self Assembling ◽  
Self Assembled

Three SAP (self-assembling peptide)-tagged fluorinases (FLAs) are successfully prepared. All three SAP-tagged FLAs bear enzymatic activity and they form nano-sized particles in aqueous solution. One of them displays improved enzyme activity, thermostability and reusability.

Use of a reversed-phase evaporation vesicle formulation for a homogeneous liposome immunoassay.

1986 ◽  
Vol 32 (9) ◽  
pp. 1687-1691 ◽  
Author(s):  
E Canova-Davis ◽  
C T Redemann ◽  
Y P Vollmer ◽  
V T Kung
Keyword(s):  
Enzyme Activity ◽  
Colorimetric Detection ◽  
Reversed Phase ◽  
Homogeneous Immunoassay ◽  
Bacterial Enzyme ◽  
Liposome Preparation ◽  
Enzyme Molecules ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Relevant Range ◽  
Serum Components

Abstract Complement-mediated release of enzyme molecules from reversed-phase evaporation vesicles serves as the basis of the sensitive homogeneous immunoassay reported here. We found it necessary to co-entrap the substrate glucose 6-phosphate with the bacterial enzyme glucose-6-phosphate dehydrogenase (EC 1.1.1.49) to protect enzyme activity during liposome preparation. Enzyme can be released specifically from these liposomes by incubation with antibody and complement. the enzyme is not merely available to substrate but is actually physically free of the liposomes. Inhibition of this complement-mediated lysis by theophylline is the basis for the homogeneous liposome immunoassay described. The assay results vary linearly with theophylline concentrations in plasma in the clinically relevant range, and serum components do not interfere. The reagents in the assay kit are stable for at least seven months when stored at 5 degrees C. No nontheophylline compounds reacted significantly with the antiserum used. The assay can be run in a kinetic format, with either ultraviolet or colorimetric detection.

scholarly journals Effects of Substrate-Binding Site Residues on the Biochemical Properties of a Tau Class Glutathione S-Transferase from Oryza sativa

Genes ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 25 ◽  
Author(s):  
Xue Yang ◽  
Jinchi Wei ◽  
Zhihai Wu ◽  
Jie Gao
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Abiotic Stress ◽  
Binding Site ◽  
Stress Responses ◽  
Stress Resistance ◽  
Substrate Binding ◽  
Biochemical Properties ◽  
Biotic And Abiotic Stress ◽  
Substrate Binding Site

Glutathione S-transferases (GSTs)—an especially plant-specific tau class of GSTs—are key enzymes involved in biotic and abiotic stress responses. To improve the stress resistance of crops via the genetic modification of GSTs, we predicted the amino acids present in the GSH binding site (G-site) and hydrophobic substrate-binding site (H-site) of OsGSTU17, a tau class GST in rice. We then examined the enzyme activity, substrate specificity, enzyme kinetics and thermodynamic stability of the mutant enzymes. Our results showed that the hydrogen bonds between Lys42, Val56, Glu68, and Ser69 of the G-site and glutathione were essential for enzyme activity and thermal stability. The hydrophobic side chains of amino acids of the H-site contributed to enzyme activity toward 4-nitrobenzyl chloride but had an inhibitory effect on enzyme activity toward 1-chloro-2,4-dinitrobenzene and cumene hydroperoxide. Different amino acids of the H-site had different effects on enzyme activity toward a different substrate, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole. Moreover, Leu112 and Phe162 were found to inhibit the catalytic efficiency of OsGSTU17 to 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, while Pro16, Leu112, and Trp165 contributed to structural stability. The results of this research enhance the understanding of the relationship between the structure and function of tau class GSTs to improve the abiotic stress resistance of crops.

scholarly journals G-6-PD Long Prairie: a new glucose-6-phosphate dehydrogenase mutant exhibiting normal sensitivity to inhibition by NADPH and accompanied by nonspherocytic hemolytic anemia

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 247-251 ◽  
Author(s):  
GJ Johnson ◽  
ME Kaplan ◽  
E Beutler
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Alternative Mechanism ◽  
Ph Optimum ◽  
Intracellular Enzyme ◽  
Chronic Hemolysis ◽  
Increased Sensitivity ◽  
Normal Sensitivity ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Heat Instability

Abstract The enzymatic properties of a new glucose-6-phosphate dehydrogenase (G- 6-PD) variant (G-6-PD Long Prairie) were studied in a white patient with chronic nonspherocytic hemolysis. The red cells were found to have 2.3%-7.7% normal enzymatic activity. The mutant enzyme exhibited marked heat instability, an increased pH optimum, a moderately decreased Km for G-6-P, and increased utilization of 2-deoxyglucose-6-phosphate and deamino NADP. The Km for NADP and Ki for NADPH were both normal. G-6-PD Long Prairie is an interesting new G-6-PD variant that demonstrates that chronic hemolysis can be associated with modestly decreased G-6-PD activity despite normal sensitivity to inhibition by NADPH. Although increased sensitivity to inhibition by NADPH has been postulated to decrease intracellular enzyme activity, resulting in enhanced susceptibility to hemolysis in certain G-6-PD variants with only moderately decreased enzymatic activity, an alternative mechanism of hemolysis, possibly enzyme thermolability, exists in G-6-PD Long Prairie.

scholarly journals Enzymatic activity measured by microcalorimetry in soil amended with organic residues

2011 ◽  
Vol 35 (4) ◽  
pp. 1167-1178 ◽  
Author(s):  
Karina Cenciani ◽  
Sueli dos Santos Freitas ◽  
Silvana Auxiliadora Missola Critter ◽  
Claudio Airoldi
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Thermal Effect ◽  
Soil Samples ◽  
Cattle Manure ◽  
Control Treatment ◽  
Municipal Sewage Sludge ◽  
Organic Residues ◽  
Earthworm Casts ◽  
Commercial Enzymes

Enzymatic activity is an important property for soil quality evaluation. Two sequences of experiments were carried out in order to evaluate the enzymatic activity in a soil (Rhodic Eutrudox) amended with cattle manure, earthworm casts, or sewage sludges from the municipalities of Barueri and Franca. The activity of commercial enzymes was measured by microcalorimetry in the same soil samples after sterilization. In the first experiment, the enzyme activities of cellulase, protease, and urease were determined in the soil samples during a three month period. In the second sequence of experiments, the thermal effect of the commercial enzymes cellulase, protease, and urease on sterilized soil samples under the same tretaments was monitored for a period of 46 days. The experimental design was randomized and arranged as factorial scheme in five treatments x seven samplings with five replications. The treatment effects were statistically evaluated by one-way analysis of variance. Tukey´s test was used to compare means at p < 0.05. The presence of different sources of organic residues increased the enzymatic activity in the sampling period. Cattle manure induced the highest enzymatic activity, followed by municipal sewage sludge, whereas earthworm casts induced the lowest activity, but differed from control treatment. The thermal effect on the enzyme activity of commercial cellulase, protease, and urease showed a variety of time peaks. These values probably oscillated due to soil physical-chemical factors affecting the enzyme activity on the residues.

scholarly journals Enzyme Characteristics of β-d-Galactosidase- and β-d-Glucuronidase-Positive Bacteria and Their Interference in Rapid Methods for Detection of Waterborne Coliforms andEscherichia coli

1998 ◽  
Vol 64 (3) ◽  
pp. 1018-1023 ◽  
Author(s):  
I. Tryland ◽  
L. Fiksdal
Keyword(s):  
Escherichia Coli ◽  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Environmental Water ◽  
Coliform Bacteria ◽  
Galactosidase Activity ◽  
Fluorogenic Substrates ◽  
Rapid Methods ◽  
E Coli ◽  
Aerococcus Viridans

ABSTRACT Bacteria which were β-d-galactosidase and β-d-glucuronidase positive or expressed only one of these enzymes were isolated from environmental water samples. The enzymatic activity of these bacteria was measured in 25-min assays by using the fluorogenic substrates 4-methylumbelliferyl-β-d-galactoside and 4-methylumbelliferyl-β-d-glucuronide. The enzyme activity, enzyme induction, and enzyme temperature characteristics of target and nontarget bacteria in assays aimed at detecting coliform bacteria and Escherichia coli were investigated. The potential interference of false-positive bacteria was evaluated. Several of the β-d-galactosidase-positive nontarget bacteria but none of the β-d-glucuronidase-positive nontarget bacteria contained unstable enzyme at 44.5°C. The activity of target bacteria was highly inducible. Nontarget bacteria were induced much less or were not induced by the inducers used. The results revealed large variations in the enzyme levels of different β-d-galactosidase- and β-d-glucuronidase-positive bacteria. The induced and noninduced β-d-glucuronidase activities ofBacillus spp. and Aerococcus viridans were approximately the same as the activities of induced E. coli. Except for some isolates identified asAeromonas spp., all of the induced and noninduced β-d-galactosidase-positive, noncoliform isolates exhibited at least 2 log units less mean β-d-galactosidase activity than induced E. coli. The noncoliform bacteria must be present in correspondingly higher concentrations than those of target bacteria to interfere in the rapid assay for detection of coliform bacteria.

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