共查询到20条相似文献,搜索用时 31 毫秒
1.
Eugenia Poliakov Susan Gentleman Preethi Chander Francis X Cunningham Jr Bella L Grigorenko Alexander V Nemuhin T Michael Redmond 《BMC biochemistry》2009,10(1):31-13
Background
β-carotene 15,15'-monooxygenase (BCMO1) catalyzes the crucial first step in vitamin A biosynthesis in animals. We wished to explore the possibility that a carbocation intermediate is formed during the cleavage reaction of BCMO1, as is seen for many isoprenoid biosynthesis enzymes, and to determine which residues in the substrate binding cleft are necessary for catalytic and substrate binding activity. To test this hypothesis, we replaced substrate cleft aromatic and acidic residues by site-directed mutagenesis. Enzymatic activity was measured in vitro using His-tag purified proteins and in vivo in a β-carotene-accumulating E. coli system. 相似文献2.
Background
In Drosophila, cuticular sex pheromones are long-chain unsaturated hydrocarbons synthesized from fatty acid precursors in epidermal cells called oenocytes. The species D. melanogaster shows sex pheromone dimorphism, with high levels of monoenes in males, and of dienes in females. Some biosynthesis enzymes are expressed both in fat body and oenocytes, rendering it difficult to estimate the exact role of oenocytes and of the transport of fatty acids from fat body to oenocytes in pheromone elaboration. To address this question, we RNAi silenced two main genes of the biosynthesis pathway, desat1 and desatF, in the oenocytes of D. melanogaster, without modifying their fat body expression. 相似文献3.
Ludmila V Roze Anindya Chanda Maris Laivenieks Randolph M Beaudry Katherine A Artymovich Anna V Koptina Deena W Awad Dina Valeeva Arthur D Jones John E Linz 《BMC biochemistry》2010,11(1):33
Background
Filamentous fungi in the genus Aspergillus produce a variety of natural products, including aflatoxin, the most potent naturally occurring carcinogen known. Aflatoxin biosynthesis, one of the most highly characterized secondary metabolic pathways, offers a model system to study secondary metabolism in eukaryotes. To control or customize biosynthesis of natural products we must understand how secondary metabolism integrates into the overall cellular metabolic network. By applying a metabolomics approach we analyzed volatile compounds synthesized by Aspergillus parasiticus in an attempt to define the association of secondary metabolism with other metabolic and cellular processes. 相似文献4.
Christina Ramel Micha Tobler Martin Meyer Laurent Bigler Marc-Olivier Ebert Barbara Schellenberg Robert Dudler 《BMC biochemistry》2009,10(1):26-9
Background
Syringolin A, an important virulence factor in the interaction of the phytopathogenic bacterium Pseudomonas syringaepv. syringaeB728a with its host plant Phaseolus vulgaris(bean), was recently shown to irreversibly inhibit eukaryotic proteasomes by a novel mechanism. Syringolin A is synthesized by a mixed non-ribosomal peptide synthetase/polyketide synthetase and consists of a tripeptide part including a twelve-membered ring with an N-terminal valine that is joined to a second valine via a very unusual ureido group. Analysis of sequence and architecture of the syringolin A synthetase gene cluster with the five open reading frames sylA-sylEallowed to formulate a biosynthesis model that explained all structural features of the tripeptide part of syringolin A but left the biosynthesis of the unusual ureido group unaccounted for. 相似文献5.
Background
Arylamine N-acetyltransferases (NATs) are important drug- and carcinogen-metabolising enzymes that catalyse the transfer of an acetyl group from a donor, such as acetyl coenzyme A, to an aromatic or heterocyclic amine, hydrazine, hydrazide or N-hydroxylamine acceptor substrate. NATs are found in eukaryotes and prokaryotes, and they may also have an endogenous function in addition to drug metabolism. For example, NAT from Mycobacterium tuberculosis has been proposed to have a role in cell wall lipid biosynthesis, and is therefore of interest as a potential drug target. To date there have been no studies investigating the kinetic mechanism of a bacterial NAT enzyme. 相似文献6.
Thomas Schmidt Malte Lenders Andrea Hillebrand Nicole van Deenen Oliver Munt Rudolf Reichelt Wolfgang Eisenreich Rainer Fischer Dirk Prüfer Christian Schulze Gronover 《BMC biochemistry》2010,11(1):11
Background
Natural rubber is a biopolymer with exceptional qualities that cannot be completely replaced using synthetic alternatives. Although several key enzymes in the rubber biosynthetic pathway have been isolated, mainly from plants such as Hevea brasiliensis, Ficus spec. and the desert shrub Parthenium argentatum, there have been no in planta functional studies, e.g. by RNA interference, due to the absence of efficient and reproducible protocols for genetic engineering. In contrast, the Russian dandelion Taraxacum koksaghyz, which has long been considered as a potential alternative source of low-cost natural rubber, has a rapid life cycle and can be genetically transformed using a simple and reliable procedure. However, there is very little molecular data available for either the rubber polymer itself or its biosynthesis in T. koksaghyz. 相似文献7.
Background
The enzyme porphobilinogen synthase (PBGS), which is central to the biosynthesis of heme, chlorophyll and cobalamins, has long been known to use a variety of metal ions and has recently been shown able to exist in two very different quaternary forms that are related to metal ion usage. This paper reports new information on the metal ion independence and quaternary structure of PBGS from the photosynthetic bacterium Rhodobacter capsulatus. 相似文献8.
Background
Normal cell cycle progression requires the precise activation and inactivation of cyclin-dependent protein kinases (CDKs), which consist of a CDK and a cyclin subunit. A novel cell cycle regulator called Speedy/Ringo shows no sequence similarity to cyclins, yet can directly bind to and activate CDKs. Speedy/Ringo proteins, which bind to and activate Cdc2 and Cdk2 in vitro, are required for the G2 to M transition during Xenopus oocyte maturation and for normal S-phase entry in cultured human cells. 相似文献9.
Background
Iron-sulfur clusters are ubiquitous and evolutionarily ancient inorganic prosthetic groups, the biosynthesis of which depends on complex protein machineries. Three distinct assembly systems involved in the maturation of cellular Fe-S proteins have been determined, designated the NIF, ISC and SUF systems. Although well described in several organisms, these machineries are poorly understood in Gram-positive bacteria. Within the Firmicutes phylum, the Enterococcus spp. genus have recently assumed importance in clinical microbiology being considered as emerging pathogens for humans, wherein Enterococcus faecalis represents the major species associated with nosocomial infections. The aim of this study was to carry out a phylogenetic analysis in Enterococcus faecalis V583 and a structural and conformational characterisation of it SufU protein. 相似文献10.
Heather B Bradshaw Neta Rimmerman Sherry Shu-Jung Hu Valery M Benton Jordyn M Stuart Kim Masuda Benjamin F Cravatt David K O'Dell J Michael Walker 《BMC biochemistry》2009,10(1):14-11
Background
N-arachidonoyl glycine (NAGly) is an endogenous signaling lipid with a wide variety of biological activity whose biosynthesis is poorly understood. Two primary biosynthetic pathways have been proposed. One suggests that NAGly is formed via an enzymatically regulated conjugation of arachidonic acid (AA) and glycine. The other suggests that NAGly is an oxidative metabolite of the endogenous cannabinoid, anandamide (AEA), through an alcohol dehydrogenase. Here using both in vitro and in vivo assays measuring metabolites with LC/MS/MS we test the hypothesis that both pathways are present in mammalian cells. 相似文献11.
Catherine Paradis-Bleau Adrian Lloyd François Sanschagrin Tom Clarke Ann Blewett Timothy DH Bugg Roger C Levesque 《BMC biochemistry》2008,9(1):33
Background
To develop antibacterial agents having novel modes of action against bacterial cell wall biosynthesis, we targeted the essential MurF enzyme of the antibiotic resistant pathogen Pseudomonas aeruginosa. MurF catalyzes the formation of a peptide bond between D-Alanyl-D-Alanine (D-Ala-D-Ala) and the cell wall precursor uridine 5'-diphosphoryl N-acetylmuramoyl-L-alanyl-D-glutamyl-meso-diaminopimelic acid (UDP-MurNAc-Ala-Glu-meso-A2pm) with the concomitant hydrolysis of ATP to ADP and inorganic phosphate, yielding UDP-N-acetylmuramyl-pentapeptide. As MurF acts on a dipeptide, we exploited a phage display approach to identify peptide ligands having high binding affinities for the enzyme. 相似文献12.
13.
Raquel S. G. R. Seixas Artur M. S. Silva Ibon Alkorta José Elguero 《Monatshefte für Chemie / Chemical Monthly》2011,18(5):731-742
Abstract
We report the synthesis and structural study of eight compounds, either quinolin-4(1H)-ones or quinolines. Tautomerism as well as (E) → (Z) and rotational isomerism were studied both experimentally (1H and 13C NMR) and theoretically [B3LYP/6-311++G(d,p)]. 相似文献14.
Background
Endoplasmic reticulum retention of misfolded cystic fibrosis transmembrane conductance regulator (CFTR) mutants and their rapid degradation is the major cause of cystic fibrosis (CF). An important goal is to understand the mechanism of how the misfolded proteins are recognized, retained, and targeted for degradation. 相似文献15.
Aejazur Rahman Saumya S Srivastava Amita Sneh Neesar Ahmed Musti V Krishnasastry 《BMC biochemistry》2010,11(1):35
Background
Mycobacterium tuberculosis is a virulent bacillus causing tuberculosis, a disease responsible for million deaths each year worldwide. In order to understand its mechanism of pathogenesis in humans and to help control tuberculosis, functions of numerous Mycobacterium tuberculosis genes are being characterized. In this study we report the dual functionality of tlyA gene product of Mycobacterium tuberculosis annotated as Rv1694, a 268 amino acid long basic protein. 相似文献16.
Background
Microbial degradation of azo dyes is commonly initiated by the reduction of the azo bond(s) by a group of NADH or NADPH dependant azoreductases with many requiring flavin as a cofactor. In this study, we report the identification of a novel flavin-free NADPH preferred azoreductase encoded by azoB in Pigmentiphaga kullae K24. 相似文献17.
Background
Triptolide is a diterpene triepoxide from the Chinese medicinal plant Tripterygium wilfordii Hook F., with known anti-inflammatory, immunosuppressive and anti-cancer properties. 相似文献18.
19.
Krzysztof Kolodziejczyk Gheorghe D. Roiban Michael Schnürch Marko D. Mihovilovic Peter Stanetty 《Monatshefte für Chemie / Chemical Monthly》2009,51(3):1349-1359
Abstract
An efficient synthesis of novel N-(3-furanyl)pyrrolecarboxamides and N-(3-furanyl)pyrazolecarboxamides is presented starting from furan-3-carboxylic acid. Two complementary strategies to 2-aryl-3-furanamines with directed ortho lithiation, functionalization of the 2-position, and subsequent cross-coupling reaction as key steps were developed. Acylation of these intermediates with appropriate acid chlorides led finally to the target compounds. 相似文献20.