Biochemical characterization of an S-adenosyl-l-methionine-dependent methyltransferase (Rv0469) of Mycobacterium tuberculosis

2013 ◽  
Vol 394 (7) ◽  
pp. 871-877 ◽  
Author(s):  
Laxman S. Meena ◽  
Puneet Chopra ◽  
Ram A. Vishwakarma ◽  
Yogendra Singh
Keyword(s):  
Fatty Acids ◽  
Mycobacterium Tuberculosis ◽  
Oleic Acid ◽  
Biochemical Characterization ◽  
Short Chain Fatty Acids ◽  
Major Constituent ◽  
Membrane Phospholipids ◽  
Tuberculostearic Acid ◽  
Olefinic Double Bond

Abstract Tuberculostearic acid (l0-methylstearic acid, TSA) is a major constituent of mycobacterial membrane phospholipids, and its biosynthesis involves the direct methylation of oleic acid esterified as a component of phospholipids. The methyltransferases of mycobacteria were long proposed to be involved in the synthesis of methyl-branched short-chain fatty acids, but direct experimental evidence is still lacking. In this study, we identified the methyltransferase encoded by umaA in Mycobacterium tuberculosis H37Rv as a novel S-adenosyl-l-methionine (SAM)-dependent methyltransferase capable of catalyzing the conversion of olefinic double bond of phospholipid-linked oleic acid to biologically essential TSA. Therefore, UmaA, catalyzing such modifications, offer a viable target for chemotherapeutic intervention.

scholarly journals Determination of the Lipid Compounds of Aristolochia Longa L. from Algeria

1970 ◽  
Vol 66 (1) ◽  
Author(s):  
Hamida Saida CHERIF ◽  
Fairouz SAIDI ◽  
Hadjila LAZOURI ◽  
Khadidja AID ◽  
Abdelhak ROUIBI ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Linoleic Acid ◽  
Essential Oil ◽  
Medicinal Plant ◽  
Palmitic Acid ◽  
Biochemical Characterization ◽  
Lipid Compounds

The present work joins in an initiative, for main objective the determination and the biochemical characterization of a medicinal plant with wide use in certain regions of Algeria. Samples of Aristoloche were collected from the region of Médéa (West of Algiers). By stream training we obtained essential oil and by hydro distillation concrete of the stalks, rhizomes and leaves. With theTLC we detect and confirm the presence of esters of Methyl in our samples. Besides, Gaz chromatography (CG), allowed us to determine the main group of fatty acids characterizing our essential oil and diluted concrete. An important proportion was showed by the palmitic acid with 22, 97 %, linoleic acid demonstrate a rate of 11, 50 %, oleic acid illustrate 7,24 %.

Microthrix parvicella, a specialized lipid consumer in anaerobic–aerobic activated sludge plants

2002 ◽  
Vol 46 (1-2) ◽  
pp. 73-80 ◽  
Author(s):  
P.H. Nielsen ◽  
P. Roslev ◽  
T.E. Dueholm ◽  
J.L. Nielsen
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Activated Sludge ◽  
Neutral Lipids ◽  
Short Chain Fatty Acids ◽  
Membrane Phospholipids ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Microthrix Parvicella ◽  
Chain Fatty Acids

The in situ physiology of the filamentous bacterium Microthrix parvicella was investigated in anaerobic-aerobic dynamic phases in activated sludge with focus on the uptake of long chain fatty acids (LCFA) and growth. When 14C-labeled oleic acid was added to activated sludge with an excessive growth of M. parvicella, only little 14C-CO2 was produced under anaerobic conditions while a lot was produced under aerobic conditions. Microautoradiographic studies revealed that M. parvicella took up oleic acid under both anaerobic and aerobic conditions, while only a few floc formers were able to take it up under anaerobic conditions. Extraction and separation of the radioactive biomass into different lipid fractions showed that the oleic acid was stored mainly as neutral lipids under anaerobic conditions, whereas conversion to membrane phospholipids occurred almost exclusively under aerobic conditions, indicating growth. The surface properties of M. parvicella and other bacteria were characterized by hydrophobic fluorescent microspheres, which showed that M. parvicella was relatively hydrophobic. Furthermore, a surface-associated extracellular lipase activity was observed, indicating the ability of M. parvicella to degrade lipids near the filament surface. The results support the hypothesis that uptake and storage of LCFA as lipids under anaerobic conditions provide an effective competition strategy against bacteria that can only take up LCFA under aerobic conditions. Thus, M. parvicella seems to be a specialized lipid consumer with a physiological potential analogous to PAOs and GAOs being able to take up LCFA (but not short chain fatty acids or glucose) under anaerobic conditions and subsequently use the storage material for growth when nitrate or oxygen are available as electron acceptors.

Biochemical Characterization of VapC46 Toxin from Mycobacterium tuberculosis

2020 ◽  
Vol 62 (6-7) ◽  
pp. 335-343
Author(s):  
Madhurima Roy ◽  
Madhuparna Bose ◽  
Kamakshi Bankoti ◽  
Anirban Kundu ◽  
Santanu Dhara ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Biochemical Characterization

scholarly journals Evidence for an Elongated Dimeric Structure of Heparin-Binding Hemagglutinin from Mycobacterium tuberculosis

2008 ◽  
Vol 190 (13) ◽  
pp. 4749-4753 ◽  
Author(s):  
Carla Esposito ◽  
Maxim V. Pethoukov ◽  
Dmitri I. Svergun ◽  
Alessia Ruggiero ◽  
Carlo Pedone ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Virulence Factor ◽  
Biochemical Characterization ◽  
Coiled Coil ◽  
Heparin Binding ◽  
Truncated Form ◽  
X Ray ◽  
Dimeric Structure ◽  
X Ray Scattering

ABSTRACT Heparin-binding hemagglutinin (HBHA) is a virulence factor of tuberculosis which is responsible for extrapulmonary dissemination of this disease. A thorough biochemical characterization of HBHA has provided experimental evidence of a coiled-coil nature of HBHA. These data, together with the low-resolution structures of a full-length form and a truncated form of HBHA obtained by small-angle X-ray scattering, have unambiguously indicated that HBHA has a dimeric structure with an elongated shape.

scholarly journals Characterization of plasma unsaturated lysophosphatidylcholines in human and rat

1999 ◽  
Vol 345 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Martine CROSET ◽  
Nicole BROSSARD ◽  
Anne POLETTE ◽  
Michel LAGARDE
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Rat Plasma ◽  
Arachidonic Acid Content ◽  
Tissue Uptake ◽  
Membrane Phospholipids ◽  
Esterified Fatty Acids ◽  
The Brain ◽  
Group Shift

Unsaturated lysophosphatidylcholines (lysoPtdCho) bound to albumin circulate in blood plasma and seem to be a novel transport system for carrying polyunsaturated fatty acids (PUFA) to tissues that are rich in these fatty acids, such as the brain. The potential of these lysoPtdCho as a significant source of PUFA for cells has been assessed by comparing their plasma concentration with that of unsaturated non-esterified fatty acids (NEFA) bound to albumin. In humans, the PUFA concentration was 25.9±3.1 nmol/ml for these lysoPtdCho, compared with 33.4±9.6 nmol/ml for NEFA; in rats the equivalent values are 14.2±0.6 and 13.1±1.1 nmol/ml respectively (means±S.E.M.). The lysoPtdCho arachidonic acid content was 2-fold (human) and 5-fold (rat) higher than that of NEFA. In human and rat plasma, unsaturated lysoPtdCho were associated mainly with albumin rather than lipoproteins. The rate and extent of the acyl group shift from the sn-2 to sn-1 position of these lysoPtdCho were studied by the incubation of 1-lyso,2-[14C]C18:2n-6-glycerophosphocholine (GPC) with plasma. The rapid isomerization of this lipid occurred at pH 7 (20% isomerization within 2 min) and was not prevented by its association with albumin. The position of the acyl group in the lysoPtdCho circulating in plasma was studied by collecting blood directly in organic solvents containing 1-lyso,2-[14C]C18:2n-6-GPC as a marker of isomerization that occurred during sampling and analysis. Approx. 50% of the PUFA was located at the sn-2 position, demonstrating that substantial concentrations of 2-acyl-lysoPtdCho are present in plasma and are available for tissue uptake, where they can be reacylated at the sn-1 position to form membrane phospholipids.

Biochemical characterization of Mycobacterium tuberculosis LexA and structural studies of its C-terminal segment

2019 ◽  
Vol 75 (1) ◽  
pp. 41-55
Author(s):  
A. V. Chandran ◽  
R. Srikalaivani ◽  
A. Paul ◽  
M. Vijayan
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cleavage Site ◽  
Biochemical Characterization ◽  
Terminal Segment ◽  
Full Length ◽  
Mutual Orientation ◽  
Crystal Formation ◽  
Wild Type ◽  
Catalytic Core

LexA is a protein that is involved in the SOS response. The protein from Mycobacterium tuberculosis and its mutants have been biochemically characterized and the structures of their catalytic segments have been determined. The protein is made up of an N-terminal segment, which includes the DNA-binding domain, and a C-terminal segment encompassing much of the catalytic domain. The two segments are defined by a cleavage site. Full-length LexA, the two segments, two point mutants involving changes in the active-site residues (S160A and K197A) and another mutant involving a change at the cleavage site (G126D) were cloned and purified. The wild-type protein autocleaves at basic pH, while the mutants do not. The wild-type and the mutant proteins dimerize and bind DNA with equal facility. The C-terminal segment also dimerizes, and it also shows a tendency to form tetramers. The C-terminal segment readily crystallized. The crystals obtained from attempts involving the full-length protein and its mutants contained only the C-terminal segment including the catalytic core and a few residues preceding it, in a dimeric or tetrameric form, indicating protein cleavage during the long period involved in crystal formation. Modes of tetramerization of the full-length protein similar to those observed for the catalytic core are feasible. A complex of M. tuberculosis LexA and the cognate SOS box could be modeled in which the mutual orientation of the two N-terminal domains differs from that in the Escherichia coli LexA–DNA complex. These results represent the first thorough characterization of M. tuberculosis LexA and provide definitive information on its structure and assembly. They also provide leads for further exploration of this important protein.

scholarly journals OBTENÇÃO E CARACTERIZAÇÃO DOS PRINCIPAIS PRODUTOS DO CAJU

2004 ◽  
Vol 22 (1) ◽  
Author(s):  
ANTÔNIO CALIXTO LIMA ◽  
NELSON HORACIO PEZOA GARCÍA ◽  
JANICE RIBEIRO LIMA
Keyword(s):  
Fatty Acids ◽  
Ascorbic Acid ◽  
Oleic Acid ◽  
Dietary Fiber ◽  
Unsaturated Fatty Acids ◽  
Ascorbic Acid Content ◽  
Total Dietary Fiber ◽  
Cashew Nut ◽  
Physical And Chemical

A presente pesquisa teve por objetivo a obtenção e caracterização de produtos derivados do caju. Para tanto, produtos da castanha-de-cajueiro comum e do pedúnculo de caju do clone CCP76 foram processados e submetidos a análises físicas e químicas. Mediante prensagem da amêndoa de castanha-de-caju obtevese a torta parcialmente desengordurada (36,41% de proteínas, 26,57% de lipídios totais e 7,86% de fibra digestiva total) e o óleo (82,74% de ácidos graxos insaturados, predominando o ácido oléico - 60,30% e o linoléico - 21,53%). Do pseudofruto do caju foi obtido o suco clarificado e concentrado a vácuo (teor de ácido ascórbico de 966,13 mg/100 g de suco) e a fibra de caju (61,21% de fibra digestiva total). Concluiu-se que os produtos originários do caju apresentam elevado potencial para a elaboração de diferentes produtos alimentícios em virtude da diversidade e riqueza na composição química da castanha e do seu pseudofruto. OBTENTION AND CHARACTERIZATION OF THE MAIN CASHEW PRODUCTS Abstract The objective of the present research was the obtention and the characterization of cashew derived products. For that, products of common cashew nut and from the peduncles of cashew from the clone CCP76 were processed and submitted to physical and chemical analysis. By pressing the cashew nut it was obtained a partially defatted meal (36.41% of proteins, 26.57% of lipids and 7.86% total dietary fiber) and the oil (82.74% of unsaturated fatty acids, predominantly oleic acid - 60.30% and the linoleic - 21.53%). From cashew fruit it was obtained a clarified and concentrated juice (ascorbic acid content of 966.13 mg/100 g of juice) and cashew fiber (61.21% of total dietary fiber). It was concluded that the products originated from cashew showed high potential for the elaboration of different food products by virtue of the diversity and richness of the cashew nut and fruit chemical composition.

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