Structural biochemistry

The methanol extracts as well as some compounds from this plant exhibited anti-inflammatory, antimicrobial activity, antioxidant, hepatoprotective and anti-cancer effect, and antiosteoporotic. On going to search for bioactive components from the Vietnamese plant, this paper reported the isolation of seven phenolic compounds including one new from the aerial parts of A. ilicifolius. The cytotoxic activity of the isolates against two cancer cell lines (HepG2 and SK-LU1) were also screened and reported herein.

5p dianmotminh02 03-05-2024 7 2   Download

Acta Crystallographica Section C: Structural Chemistry specializes in the rapid dissemination of high-quality detailed studies of novel and challenging crystal and molecular structures of interest in the fields of chemistry, biochemistry, mineralogy, pharmacology, physics and materials science. The unique checking, editing and publishing facilities of the journal ensure the highest standards of structural reliability and presentation, while providing for reports on studies involving special techniques or difficult crystalline materials.

22p runordie3 27-06-2022 11 2   Download

The human b-globin gene locus is the subject of intense study, and over the past two decades a wealth of information has accumulated on how tissue-specific and stage-specific expression of its genes is achieved. The data are extensive and it would be difficult, if not impossible, to formulate a comprehensive model integrating every aspect of what is currently known. In this review, we introduce the fundamental characteristics of globin locus regulation as well as questions on which much of the current research is predicated.

11p system191 01-06-2013 44 3   Download

Mer belongs to the Tyro 3 family of receptor tyrosine kinases (RTKs). Together with Axl and Rse, the three RTKs are believed to play important functional roles in the male gonads because gene knockout male mice lacking all of these receptors are infertile. In the present study, postnatal expression of Axl and Rse in mouse testes decreased during maturation while expression of Mer increased age-dependently during testicular development.

12p system191 01-06-2013 43 2   Download

With the aim to distinguish between local and global conformational changes induced by trifluoroethanol in RNase A, spectroscopic and activity measurements in combination with proteolysis by unspecific proteases have been exploited for probing structural transitions of RNase A as a function of trifluoroethanol concentration. At 30% (v/v) trifluoroethanol (pH 8.0; 25 °C), circular dichroism and fluorescence spectroscopy indicate a cooperative collapse of the tertiary structure of RNase A coinciding with the loss of its enzymatic activity....

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An unconventional phospholipase D (PLD) activity was identified recently in Saccharomyces cerevisiae which is Ca2+-dependent, preferentially hydrolyses phosphatidylethanolamine (PtdEtn) and phosphatidylserine and does not catalyse a transphosphatidylation with primary short-chain alcohols. We have characterized the cytosolic and membrane-bound forms of the yeast PtdEtn-PLD and examined the regulation of its activity under certain growth, nutritional and stress conditions. Both forms of PtdEtn-PLD activity were similarly activated by Ca2+ ions in a biphasic manner.

10p system191 01-06-2013 35 3   Download

The goal of this study was to determine the effects of a putative specific cytosolic phospholipase A2 inhibitor, arachidonyl trifluoromethyl ketone (AACOCF3), on arachidonic acid (AA) release and lipid mediator biosynthesis by ionophore-stimulated human neutrophils. Initial studies indicated that AACOCF3 at concentrations 0–10 lM did not affect AA release from neutrophils. In contrast, AACOCF3 potently inhibited leukotriene B4 formation by ionophore-stimulated neutrophils (IC50  2.5 lM).

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The design of b-glycosidases with planed substrate specificity for biotechnological application has received little attention. This is mostly a consequence of the lack of data on the molecular basis of the b-glycosidase specificity, namely data on the energy of the noncovalent interactions in the enzymetransition state complex. In an attempt to fill this gap, sitedirected mutagenesis and enzyme steady-state kinetic experiments with different substrates were conducted, using as model a digestive b-glycosidase (glycoside hydrolase family 1) from Spodoptera frugiperda (Lepidoptera) (Sfbgly50).

10p system191 01-06-2013 38 3   Download

Department of Medical Biochemistry and Biology, University of Bari, Italy; 2Department of Zoology, Laboratory of Histology and Comparative Anatomy, University of Bari, Italy; 3Center for the Study of Mitochondria and Energy Metabolism (CNR) Bari, Italy Mitochondrial bioenergetic impairment has been found in the organelles isolated from rat liver during the prereplicative phase of liver regeneration.

9p system191 01-06-2013 33 3   Download

The case of homologous monomeric c-type and oligomeric b-type crystallins has been described and analyzed in evolutionary terms. Data and hypotheses from molecular genetics and structural investigations converge and suggest a novel three-phase model for the evolutionary history of crystallin-type proteins. In the divergent cascades of monomeric and oligomeric crystallins, a pivotal role was played by alterations in the gene segments encoding the C-terminal extensions and the intermotif or interdomain linker peptides.

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An immuno-homologue of maize Ca2+/calmodulin (CaM)dependent protein kinase with a molecular mass of 72 kDa was identified in pea. The pea kinase (PsCCaMK) was upregulated in roots in response to low temperature and increased salinity. Exogenous Ca2+ application increased the kinase level and the response was faster than that obtained following stress application. Low temperaturemediated, but not salinity-mediated stress kinase increase was inhibited by the application of EGTA and W7, a CaM inhibitor....

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Sensitization to cockroach allergens is associated with the development of asthma. Bla g 1 is a German cockroach allergen that shows allergenic cross-reactivity with American cockroach allergen, Per a 1, and has a molecular structure composed of multiple tandem amino-acid repeats. Two consecutive repeats are not identical but form a duplex that constitutes a basic molecular unit of Bla g 1. By molecular mass, purified natural Bla g 1 would contain approximately two duplexes.

7p system191 01-06-2013 43 4   Download

Introducing site-directed mutations in surface-exposed residues of subunit II of the heme aa3 cytochrome c oxidase of Paracoccus denitrificans, we analyze the kinetic parameters of electron transfer from reduced horse heart cytochrome c. Specifically we address the following issues: (a) which residues on oxidase contribute to the docking site for cytochrome c, (b) is an aromatic side chain required for electron entry from cytochrome c, and (c) what is the molecular basis for the previously observed biphasic reaction kinetics....

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A series of trehalose-based oligosaccharides were isolated from the cytoplasmic fraction of Mycobacterium smegmatis and purified by gel-filtration and paper chromatography and TLC. Their structures were determined by HPLC and GLC to determine sugar composition and ratios, MALDI-TOF MS to measure molecular mass, methylation analysis to determine linkages, 1H-NMR to obtain anomeric configurations of glycosidic linkages, and exoglycosidase digestions followed by TLC to determine sequences and anomeric configurations of the monosaccharides....

8p system191 01-06-2013 33 3   Download

Trypanosoma brucei is the cause of the diseases known as sleeping sickness in humans (T. brucei ssp. gambiense and ssp. rhodesiense) and ngana in domestic animals (T. brucei brucei) in Africa. Procyclic trypomastigotes, the tsetse vector stage, express a surface-bound trans-sialidase that transfers sialic acid to the glycosylphosphatidylinositol anchor of procyclin, a surface glycoprotein covering the parasite surface. Trans-sialidase is a unique enzyme expressed by a few trypanosomatids that allows them to scavenge sialic acid from sialylated compounds present in the infected host. ...

10p system191 01-06-2013 44 4   Download

Laboratory for Lipoprotein Chemistry and 4Flanders Interuniversity Institute for Biotechnology, Department of Medical Protein Research, Faculty of Medicine, Department of Biochemistry, Ghent University, Belgium; 2Laboratory of Biomolecular Dynamics, Katholieke Universiteit Leuven, Belgium; 3Ecole Normale Supe´rieure, Paris, France Penetratin is a 16-amino-acid peptide, derived from the homeodomain of antennapedia, a Drosophila transcription factor, which can be used as a vector for the intracellular delivery of peptides or oligonucleotides....

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In the biosynthesis of the antiarrhythmic alkaloid ajmaline, polyneuridine aldehyde esterase (PNAE) catalyses a central reaction by transforming polyneuridine aldehyde into epivellosimine, which is the immediate precursor for the synthesis of the ajmalane skeleton. The PNAE cDNA was previously heterologously expressed in E. coli. Sequence alignments indicated that PNAE has a 43% identity to a hydroxynitrile lyase from Hevea brasiliensis, which is a member of the a/b hydrolase superfamily. The catalytic triad, which is typical for this family, is conserved.

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The present work reports isolation and characterization of a highly glycosylated protein from bovine milk fat globule membranes, known as PAS III. Partial amino-acid sequencing of the purified protein allowed construction of degenerate oligonucleotide primers, enabling isolation of a full-length cDNA encoding a protein of 330 amino-acid residues. N-terminal amino-acid sequencing of derived peptides and the purified protein confirmed 76% of the sequence and demonstrated presence of a cleavable signal peptide of 23 residues, leaving a mature protein of 307 amino acids.

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Oxford Centre for Molecular Sciences and the Dyson Perrins Laboratory, Oxford, UK; 2Department of Biochemistry, National Defence Medical Centre, Taipei, Taiwan; 3Department of Pharmacy and Pharmacology, The University of Bath, UK Deacetoxycephalosporin C synthase (DAOCS) catalyses the oxidative ring expansion of penicillin N, the committed step in the biosynthesis of cephamycin C by Streptomyces clavuligerus.

5p system191 01-06-2013 23 2   Download

P-glycoprotein (Pgp), a membrane pump often responsible for the multidrug resistance of cancer cells, undergoes conformational changes in the presence of substrates/modulators, or upon ATP depletion, reflected by its enhanced reactivity with the UIC2 monoclonal antibody. When the UIC2-shift was elicited by certain modulators (e.g. cyclosporin A or vinblastine, but not with verapamil or Tween 80), the subsequent binding of other monoclonal anti-Pgp Ig sharing epitopes with UIC2 (e.g. MM12.10) was abolished [Nagy, H., Goda, K., Arceci, R., Cianfriglia, M., ´ Mechetner, E. & Szabo Jr, G.

6p system191 01-06-2013 61 6   Download