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101.
Nirmal K. Prasad Vaibhav Vindal Vikash Kumar Ashish Kabra Navneet Phogat Manoj Kumar 《Journal of molecular modeling》2011,17(3):533-541
Lignin, a major constituent of plant call wall, is a phenolic heteropolymer. It plays a major role in the development of plants
and their defense mechanism against pathogens. Therefore Lignin biosynthesis is one of the critical metabolic pathways. In
lignin biosynthesis, the Cinnamoyl CoA reductase is a key enzyme which catalyzes the first step in the pathway. Cinnamoyl
CoA reductase provides the substrates which represent the main transitional molecules of lignin biosynthesis pathway, exhibits
a high in vitro kinetic preference for feruloyl CoA. In present study, the three-dimensional model of cinnamoyl CoA reductase was constructed
based on the crystal structure of Grape Dihydroflavonol 4-Reductase. Furthermore, the docking studies were performed to understand
the substrate interactions to the active site of CCR. It showed that residues ARG51, ASN52, ASP54 and ASN58 were involved
in substrate binding. We also suggest that residue ARG51 in CCR is the determinant residue in competitive inhibition of other
substrates. This structural and docking information have prospective implications to understand the mechanism of CCR enzymatic
reaction with feruloyl CoA, however the approach will be applicable in prediction of substrates and engineering 3D structures
of other enzymes as well. 相似文献
102.
103.
The Saccharomyces cerevisiae YLL012/YEH1, YLR020/YEH2, and TGL1 genes encode a novel family of membrane-anchored lipases that are required for steryl ester hydrolysis
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Sterol homeostasis in eukaryotic cells relies on the reciprocal interconversion of free sterols and steryl esters. The formation of steryl esters is well characterized, but the mechanisms that control steryl ester mobilization upon cellular demand are less well understood. We have identified a family of three lipases of Saccharomyces cerevisiae that are required for efficient steryl ester mobilization. These lipases, encoded by YLL012/YEH1, YLR020/YEH2, and TGL1, are paralogues of the mammalian acid lipase family, which is composed of the lysosomal acid lipase, the gastric lipase, and four novel as yet uncharacterized human open reading frames. Lipase triple-mutant yeast cells are completely blocked in steryl ester hydrolysis but do not affect the mobilization of triacylglycerols, indicating that the three lipases are required for steryl ester mobilization in vivo. Lipase single mutants mobilize steryl esters to various degrees, indicating partial functional redundancy of the three gene products. Lipase double-mutant cells in which the third lipase is expressed from the inducible GAL1 promoter have greatly reduced steady-state levels of steryl esters, indicating that overexpression of any of the three lipases is sufficient for steryl ester mobilization in vivo. The three yeast enzymes constitute a novel class of membrane-anchored lipases that differ in topology and subcellular localization. 相似文献
104.
Choudhary A Tiwari RP Koul A Chanana V Gupta S Rishi P 《Molecular and cellular biochemistry》2005,270(1-2):167-175
Salmonella enterica serovar Typhimurium and its surface components were assessed for their inflammatory potential by footpad oedema test using plethysmometer. Inflammation was found to be the highest when outer membrane proteins (OMPs) were used as inflammagen followed by lipid associated protein-lipopolysaccharide complex (LAP-LPS) and lipopolysaccharides (LPS). Inflammation produced by OMPs was found to be comparable to that by carrageenan (a known positive inflammagen). However, injection of L-histidine (an antioxidant) prior to administration of carrageenan or Salmonella enterica serovar Typhimurium inhibited the inflammation, which indicated the involvement of oxidants during inflammatory response. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and nitric oxide (NO) production by peritoneal macrophages from infected mice exhibited a significant increase as compared to those of the immunized mice. In contrast, glutathione production was found to be the maximum in the macrophages taken from OMPs-immunized mice followed by LAP-LPS and LPS alone. The biochemical studies correlated well with histopathological studies of intestinal tissue of animals from various groups. Based upon these parameters, inflammation seems to be modulated by OMPs and LAP-LPS, which may be because of the protein moieties present in the components. Hence, immunization with protein moieties having L-histidine or L-histidine-like structures may suggest an alternative to the potential therapeutic values of anti-inflammatory drugs. Thus the results of this study form the basis for evaluating these antigens (either alone or in combination with polysaccharides) for preventive intervention rather than therapeutic. (Mol Cell Biochem 270: 167–175, 2005) 相似文献
105.
Carbonic anhydrase in relation to higher plants 总被引:12,自引:0,他引:12
The review incorporates recent information on carbonic anhydrase (CA, EC: 4.2.1.1) pertaining to types, homology, regulation, purification, in vitro stability, and biological functions with special reference to higher plants. CA, a ubiquitous enzyme in prokaryotes and higher organisms represented by four distinct families, is involved in diverse biological processes, including pH regulation, CO2 transfer, ion exchange, respiration, and photosynthetic CO2 fixation. CA from higher plants traces its origin with prokaryotes and exhibits compartmentalization among their organs, tissues, and cellular organelles commensurate with specific functions. In leaves, CA represents 1–20 % of total soluble protein and abundance next only to ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) in chloroplast, facilitating CO2 supply to phosphoenol pyruvate carboxylase in C4 and CAM plants and RuBPCO in C3 plants. It confers special significance to CA as an efficient biochemical marker for carbon sequestration and environmental amelioration in the current global warming scenario linked with elevated CO2 concentrations. 相似文献
106.
Alone DP Tiwari AK Mandal L Li M Mechler BM Roy JK 《The International journal of developmental biology》2005,49(7):873-879
In an effort to identify the role of Rab11, a small GTP binding protein, during Drosophila differentiation, phenotypic manifestations associated with different alleles of Rab11 were studied. The phenotypes ranged from eye-defects, bristle abnormalities and sterility to lethality during various developmental stages. In this paper, our focus is targeted on eye defects caused by Rab11 mutations. A novel P-element insertion in the Rab11 locus, Rab11mo, displayed characteristic retinal anomalies, which could be reverted by P-element excision and expression of Rab11+ transgenes. During larval development, Rab11 is widely synthesized in photoreceptor cells and localizes to the rhabdomeres and lamina neuropil in adult eyes. Photoreceptors and associated bristles failed to be formed in homozygous clones generated in Rab11EP(3)3017 eyes. Decreased levels of Rab11 protein and increased cell death in Rab11mo third-instar larval eye-antennal discs suggest that the retinal defects originate during larval development. Our data indicate a requirement for Rab11 in ommatidial differentiation during Drosophila eye development. 相似文献
107.
108.
109.
Fowler AS Tiwari KN Campbell SR Secrist JA 《Nucleosides, nucleotides & nucleic acids》2005,24(5-7):533-537
N4-Acetyl-1-(2, 3-di-O-acetyl-4-thio-beta-D-arabinofuranosyl) cytosine (2) was synthesized in three steps from 1-(4-thio-beta-D-arabinofuranosyl) cytosine (1). The reaction of this partially blocked 4'-thio-ara-C derivative 2 with 2-chloro-4H-1,3,2-benzodioxaphosphorin-4-one gave the 5-phosphitylate derivative 3, which on reaction with pyrophosphate gave the 5'-nucleosidylcyclotriphosphite 4. Product 4 was then oxidized with iodine/pyridine/water and deblocked with concentrated ammonium hydroxide to provide the desired 4'-thio-ara-C-5'-triphosphate 5. This triphosphate 5 was converted to 4'-thio-ara-C -5'-monophosphate 6 by treatment with snake venom phosphodiesterase I. The details of the synthesis, purification, and characterization of both nucleotides are described. 相似文献
110.
1-(2-Fluoro-2-deoxy-beta-D-drabinofuranosyl) uracil (5) and 1-(2-fluoro-2-deoxy-beta-D-arabinofuranosyl)cytosine (6) were synthesized as reported earlier. Both of these compounds were converted into 2'-fluoro-2'-deoxy-3'-C-ethynyl and 3'-C-vinyl-beta-D-lyxofuranosyl nuclearsides (16-19) by a multistep sequence. All these new nucleosides were evaluated against seven human tumor cell lines in vitro. 相似文献