scholarly journals Molecular cloning, expression and characterization of a ubiquitin conjugation enzyme (E217kB) highly expressed in rat testis

1995 ◽  
Vol 305 (1) ◽  
pp. 125-132 ◽  
Author(s):  
S S Wing ◽  
P Jain
Keyword(s):  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Histone H2a ◽  
Repair Gene ◽  
Ubiquitin System ◽  
Dna Repair Gene ◽  
Ubiquitin Conjugation ◽  
Molecular Masses ◽  
Ubiquitin Conjugating Enzymes

Ubiquitin-conjugating enzymes (E2s) play a key role in ubiquitin-mediated proteolysis by catalysing the conjugation of ubiquitin to protein substrates. We have previously reported the cDNA cloning of a 14 kDa conjugating enzyme [E2(14)k; Wing, Dumas and Banville (1992) J. Biol. Chem. 267, 6495-6501] that efficiently supported ubiquitination and protein degradation in reticulocyte extracts. Surprisingly, the structure of this E2 was markedly more similar to the Saccharomyces cerevisiae DNA repair gene RAD6, than to the S. cerevisiae UBC4/UBC5 genes which are required for the degradation of short-lived proteins and support much of the ubiquitination of yeast proteins. This suggested that mammalian homologues of UBC4/UBC5 remained to be identified. Using oligonucleotides derived from the S. cerevisiae UBC4 sequence as primers in a PCR reaction with rat muscle cDNA as a template, a 390 bp DNA fragment was amplified which predicted an amino acid sequence that was 83% identical to yeast UBC4. Screening a rat testes cDNA library identified a family of cDNAs which predicted two very similar proteins with basic pIs and molecular masses of approx. 16,700 Da. Isoform 2E was expressed in Escherichia coli and purified to homogeneity. It supported ubiquitination to reticulocyte and testis proteins more rapidly in vitro and produced larger conjugates than E2(14)k. Examination of RNA from different tissues indicated that this type of E2 was expressed in a broad spectrum of tissues but at particularly high levels in the testis. Fractionation of a testis extract by anion-exchange chromatography identified several putative ubiquitin protein ligase activities with which this E2 could interact in promoting conjugation of ubiquitin to proteins. One of these activities supported conjugation of ubiquitin to histone H2A, a substrate degraded in the ubiquitin system by a non-N-end rule mechanism. This paper reports the first cloning of a apparent mammalian homologue of S. cerevisiae UBC4/UBC5. Its high expression in testis and ability to efficiently support conjugation to testis proteins suggest that this family of E2s may play a role in the proteolysis that occurs during spermatogenesis.

Ca2+-binding proteins of cilia and infraciliary lattice ofParamecium tetraurelia: their phosphorylation by purified endogenous Ca2+-dependent protein kinases

2002 ◽  
Vol 115 (9) ◽  
pp. 1973-1984
Author(s):  
Kwanghee Kim ◽  
Min Son ◽  
Joan B. Peterson ◽  
David L. Nelson
Keyword(s):  
Protein Kinases ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Soluble Fraction ◽  
Biological Activities ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Paramecium Tetraurelia ◽  
Dependent Protein

We purified two small, acidic calcium-binding proteins(ParameciumCa2+-binding proteins, PCBP-25α and PCBP-25β) from Paramecium tetraurelia by Ca2+-dependent chromatography on phenyl-Sepharose and by anion-exchange chromatography. The proteins were immunologically distinct. Monoclonal antibodies against PCBP-25β did not react with PCBP-25α, and antibodies against centrin from Chlamydomonas reacted with PCBP-25α but not with PCBP-25β. Like the centrins described previously, both PCBPs were associated with the infraciliary lattice (ICL), a fibrillar cytoskeletal element in Paramecium. Both were also present in isolated cilia, from which they could be released (with dynein) by a high-salt wash, and both PCBPs cosedimented with dynein in a sucrose gradient. PCBP-25β was especially prominent in cilia and in the deciliation supernatant, a soluble fraction released during the process of deciliation. The results of immunoreactivity and localization experiments suggest that PCBP-25α is a Paramecium centrin and that PCBP-25β is a distinct Ca2+-binding protein that confers Ca2+ sensitivity on some component of the cilium, ciliary basal body or ICL.We characterized these proteins and Paramecium calmodulin as substrates for two Ca2+-dependent protein kinases purified from Paramecium. PCBP-25α and calmodulin were in vitro substrates for one of the two Ca2+-dependent protein kinases (CaPK-2), but only PCBP-25α was phosphorylated by CaPK-1. These results raise the possibility that the biological activities of PCBP-25α and calmodulin are regulated by phosphorylation.

scholarly journals Role of individual gamma-carboxyglutamic acid residues of activated human protein C in defining its in vitro anticoagulant activity

Blood ◽  
1992 ◽  
Vol 80 (4) ◽  
pp. 942-952 ◽  
Author(s):  
L Zhang ◽  
A Jhingan ◽  
FJ Castellino
Keyword(s):  
Protein C ◽  
Anticoagulant Activity ◽  
Coagulation Factor ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Factor Ix ◽  
Human Protein ◽  
Complete Disappearance ◽  
Carboxyglutamic Acid

Abstract To evaluate the contributions of individual gamma-carboxyglutamic acid (gla) residues to the overall Ca(2+)-dependent anticoagulant activity of activated human protein C (APC), we used recombinant (r) DNA technology to generate protein C (PC) variants in which each of the gla precursor glutamic acid (E) residues (positions 6, 7, 14, 16, 19, 20, 25, 26, and 29) was separately altered to aspartic acid (D). In one case, a gla26V mutation ([gla26V]r-PC) was constructed because a patient with this particular substitution in coagulation factor IX had been previously identified. Two additional r-PC mutants were generated, viz, an r-PC variant containing a substitution at arginine (R) 15 ([R15]r-PC), because this particular R residue is conserved in all gla- containing blood coagulation proteins, as well as a variant r-PC with substitution of an E at position 32 ([F31L, Q32E]r-PC), because gla residues are found in other proteins at this sequence location. This latter protein did undergo gamma-carboxylation at the newly inserted E32 position. For each of the 11 recombinant variants, a subpopulation of PC molecules that were gamma-carboxylated at all nonmutated gla- precursor E residues has been purified by anion exchange chromatography and, where necessary, affinity chromatography on an antihuman PC column. The r-PC muteins were converted to their respective r-APC forms and assayed for their amidolytic activities and Ca(2+)-dependent anticoagulant properties. While no significant differences were found between wild-type (wt) r-APC and r-APC mutants in the amidolytic assays, lack of a single gla residue at any of the following locations, viz, 7, 16, 20, or 26, led to virtual complete disappearance of the Ca(2+)-dependent anticoagulant activity of the relevant r-APC mutant, as compared with its wt counterpart. On the other hand, single eliminations of any of the gla residues located at positions 6, 14, or 19 of r-APC resulted in variant recombinant molecules with substantial anticoagulant activity (80% to 92%), relative to wtr-APC. Mutation of gla residues at positions 25 and 29 resulted in r-APC variants with significant but low (24% and 9% of wtr-APC, respectively) levels of anticoagulant activity. The variant, [R15L]r-APC, possessed only 19% of the anticoagulant activity of wrt-APC, while inclusion of gla at position 32 in the variant, [F31L, Q32gla]r-APC, resulted in a recombinant enzyme with an anticoagulant activity equivalent to that of wtr-APC.

scholarly journals Prebiotic Activity of Poly- and Oligosaccharides Obtained from Plantago major L. Leaves

2020 ◽  
Vol 10 (8) ◽  
pp. 2648 ◽  
Author(s):  
Paolina Lukova ◽  
Mariana Nikolova ◽  
Emmanuel Petit ◽  
Redouan Elboutachfaiti ◽  
Tonka Vasileva ◽  
...  
Keyword(s):  
Size Exclusion Chromatography ◽  
Galacturonic Acid ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Plantago Major ◽  
Prebiotic Activity ◽  
Molecular Fraction ◽  
Exclusion Chromatography

The aim of the present study was to evaluate the prebiotic potential of Plantago major L. leaves water-extractable polysaccharide (PWPs) and its lower molecular fractions. The structure of PWPs was investigated by high pressure anion exchange chromatography (HPAEC), size exclusion chromatography coupled with multi-angle laser light scattering detector (SEC-MALLS) and Fourier-transform infrared (FTIR) spectroscopy. The chemical composition and monosaccharide analyses showed that galacturonic acid was the main monosaccharide of PWPs followed by glucose, arabinose, galactose, rhamnose and xylose. FTIR study indicated a strong characteristic absorption peak at 1550 cm−1 corresponding to the vibration of COO− group of galacturonic acid. The PWPs was subjected to hydrolysis using commercial enzymes to obtain P. major low molecular fraction (PLM) which was successively separated by size exclusion chromatography on Biogel P2. PWPs and PLM were examined for in vitro prebiotic activity using various assays. Results gave evidence for changes in optical density of the bacteria cells and pH of the growth medium. A heterofermentative process with a lactate/acetate ratio ranged from 1:1 to 1:5 was observed. The ability of PLM to stimulate the production of certain probiotic bacteria glycohydrolases and to be fermented by Lactobacillus sp. strains was successfully proved.

scholarly journals Evidence for N-linked glycosylation in Toxoplasma gondii

1993 ◽  
Vol 291 (3) ◽  
pp. 713-721 ◽  
Author(s):  
M Odenthal-Schnittler ◽  
S Tomavo ◽  
D Becker ◽  
J F Dubremetz ◽  
R T Schwarz
Keyword(s):  
Toxoplasma Gondii ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Surface Glycoprotein ◽  
Common Precursor ◽  
The Common ◽  
Oligosaccharide Structures

In this paper we report experiments demonstrating the presence of N-linked oligosaccharide structures in Toxoplasma gondii tachyzoites, providing the first direct biochemical evidence that this sporozoan parasite is capable of synthesizing N-linked glycans. The tachyzoite surface glycoprotein gp23 was metabolically labelled with [3H]glucosamine and [3H]mannose. Gel-filtration chromatography on Bio-Gel P4 columns produced four radiolabelled N-linked glycopeptides which were sensitive to peptidase-N-glycanase F, but resistant to endoglycosidases H and F. Using chemical analysis and exoglycosidase digestions followed by Dionex-high-pH anion-exchange chromatography and size fractionation on Bio-Gel P4 we show that gp23 has N-linked glycans in the hybrid- or complex-type structure composed of N-acetylgalactosamine, N-acetylglucosamine and mannose and devoid of sialic acid and fucose residues. In addition, the sensitivity of glycopeptides from glycoprotein extracts to endoglycosidases H and F revealed the in vivo synthesis of oligomannose-type structures by T. gondii tachyzoites. We have extended these findings by demonstrating the ability of T. gondii microsomes to synthesize in vitro a glucosylated lipid-bound high-mannose structure (Glc3Man9GlcNAc2) that is assumed to be identical with the common precursor for N-glycosylation in eukaryotes.

scholarly journals A Novel Hemagglutinin with Antiproliferative Activity against Tumor Cells from the Hallucinogenic MushroomBoletus speciosus

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jian Sun ◽  
Tzi-Bun Ng ◽  
Hexiang Wang ◽  
Guoqing Zhang
Keyword(s):  
Cation Exchange ◽  
Antiproliferative Activity ◽  
Gel Filtration ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Lymphocytic Leukemia ◽  
Hemagglutinating Activity ◽  
Cation Exchange Chromatography ◽  
Type Ab

Little was known about bioactive compounds from the hallucinogenic mushroomBoletus speciosus. In the present study, a hemagglutinin (BSH,B. speciosushemagglutinin) was isolated from its fruiting bodies and enzymatic properties were also tested. The chromatographic procedure utilized comprised anion exchange chromatography on Q-Sepharose, cation exchange chromatography on CM-Cellulose, cation exchange chromatography on SP-Sepharose, and gel filtration by FPLC on Superdex 75. The hemagglutinin was a homodimer which was estimated to be approximately 31 kDa in size. The activity of BSH was stable up to 60°C, while there was a precipitous drop in activity when the temperature was elevated to 70°C. BSH retained 25% hemagglutinating activity when exposed to 100 mM NaOH and 25 mM HCl. The activity was potently inhibited by 1.25 mM Hg2+and slightly inhibited by Fe2+, Ca2+, and Pb2+. None of the sugars tested showed inhibition towards BSH. Its hemagglutinating activity towards human erythrocytes type A, type B, and type AB was higher than type O. The hemagglutinin showed antiproliferative activity towards hepatoma Hep G2 cells and mouse lymphocytic leukemia cells (L1210)in vitro, with IC50of 4.7 μM and 7.0 μM, respectively. It also exhibited HIV-1 reverse transcriptase inhibitory activity with an IC50of 7.1 μM.

scholarly journals Developmental Defects and Male Sterility in Mice Lacking the Ubiquitin-Like DNA Repair Gene mHR23B

2002 ◽  
Vol 22 (4) ◽  
pp. 1233-1245 ◽  
Author(s):  
Jessica M. Y. Ng ◽  
Harry Vrieling ◽  
Kaoru Sugasawa ◽  
Marja P. Ooms ◽  
J. Anton Grootegoed ◽  
...  
Keyword(s):  
Male Sterility ◽  
Excision Repair ◽  
High Rate ◽  
Repair Gene ◽  
Developmental Defects ◽  
Mouse Mutants ◽  
Dna Repair Gene ◽  
Ubiquitin Proteasome ◽  
In Vitro Repair

ABSTRACT mHR23B encodes one of the two mammalian homologs of Saccharomyces cerevisiae RAD23, a ubiquitin-like fusion protein involved in nucleotide excision repair (NER). Part of mHR23B is complexed with the XPC protein, and this heterodimer functions as the main damage detector and initiator of global genome NER. While XPC defects exist in humans and mice, mutations for mHR23A and mHR23B are not known. Here, we present a mouse model for mHR23B. Unlike XPC-deficient cells, mHR23B−/− mouse embryonic fibroblasts are not UV sensitive and retain the repair characteristics of wild-type cells. In agreement with the results of in vitro repair studies, this indicates that mHR23A can functionally replace mHR23B in NER. Unexpectedly, mHR23B−/− mice show impaired embryonic development and a high rate (90%) of intrauterine or neonatal death. Surviving animals display a variety of abnormalities, including retarded growth, facial dysmorphology, and male sterility. Such abnormalities are not observed in XPC and other NER-deficient mouse mutants and point to a separate function of mHR23B in development. This function may involve regulation of protein stability via the ubiquitin/proteasome pathway and is not or only in part compensated for by mHR23A.

In vivo behaviour of rat transferrin bearing a hybrid glycan and its interaction with macrophages

1992 ◽  
Vol 70 (8) ◽  
pp. 636-642 ◽  
Author(s):  
Wei-Li Hu ◽  
Paul A. Chindemi ◽  
Erwin Regoeczi
Keyword(s):  
Bone Marrow ◽  
Principal Component ◽  
Anion Exchange Chromatography ◽  
Sialic Acid Residue ◽  
Exchange Chromatography ◽  
Lectin Affinity Chromatography ◽  
Human Transferrin ◽  
Excess Iron

Production of rat transferrin containing a single hybrid glycan was induced by treating rats with swainsonine, an inhibitor of α-mannosidase II. The principal component of this variant transferrin containing one sialic acid residue per mole of protein was separated from other forms of transferrin by anion-exchange chromatography, followed by lectin affinity chromatography. Transferrin bearing the hybrid glycan was degraded in vivo with a half-life of 14 h as compared with 40 h for transferrin containing a standard diantennary glycan. By using 125I-labelled tyramine-cellobiose, a label whose discharge from lysosomes is strongly retarded, organs rich in reticuloendothelial elements (liver, bone marrow, lungs, and spleen) were identified as the major sites of catabolism of the transferrin variant. The liver took up more 59Fe from the variant (26% of the dose in 90 min) than from control rat transferrin (12%). The excess iron uptake was reduced by the intravenous injection of either human transferrin or ovalbumin, and it was abolished by administering both. Macrophages from bone marrow and lungs degraded the transferrin variant in vitro. The degradation was significantly enhanced when transferrin receptors were blocked by human transferrin, and it was significantly reduced by ovalbumin and methyl glucopyranoside.Key words: glycoprotein, iron metabolism, lectin, plasma protein metabolism, transferrin.

scholarly journals Mutations in RAD6, a yeast gene encoding a ubiquitin-conjugating enzyme, stimulate retrotransposition.

1990 ◽  
Vol 10 (3) ◽  
pp. 1017-1022 ◽  
Author(s):  
S Picologlou ◽  
N Brown ◽  
S W Liebman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fold Increase ◽  
Yeast Gene ◽  
Gene Encoding ◽  
Repair Gene ◽  
Dna Repair Gene ◽  
Ubiquitin Conjugating Enzyme ◽  
First Time ◽  
Conjugating Enzyme

The Saccharomyces cerevisiae DNA repair gene RAD6 encodes a ubiquitin-conjugating enzyme which polyubiquitinates histones in vitro. Here we show that mutations in rad6 increase the frequency of transposition of the retrotransposon Ty into the CAN1 and URA3 loci. Using isogenic RAD6 and rad6 strains, we measured a more than 100-fold increase in the spontaneous rate of retrotransposition due to rad6, although there was no increase in the Ty message level. This is the first time that a mutation in a host gene has been shown to result in an increased rate of retrotransposition.

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