|
| ||
|
|
||
Acid Biosynthetic Pathway (acid + biosynthetic_pathway)
Kinds of Acid Biosynthetic Pathway Selected AbstractsAntituberculosis Agents and an Inhibitor of the para -Aminobenzoic Acid Biosynthetic Pathway from Hydnocarpus anthelminthica SeedsCHEMISTRY & BIODIVERSITY, Issue 8 2010Jun-Feng Wang Abstract Investigation on the extracts of Hydnocarpus anthelminthica seeds led to the isolation of three new compounds, anthelminthicins A,C (1,3, resp.), and two known ones, namely chaulmoogric acid (4) and ethyl chaulmoograte (5). Their structures were determined mainly by using spectroscopic techniques. The absolute configuration at the cyclopentenyl moiety of compound 2 was rationalized by quantum calculations. Base hydrolysis, followed by optical-rotation comparison, allowed assignment of the configuration of chaulmoogric-acid moiety of compounds 3 and 5. Biological assays revealed that compounds 1,5 significantly inhibit Mycobacterium tuberculosis (MTB) growth with MIC values of 5.54, 16.70, 4.38, 9.82, and 16.80,,M, respectively. Compound 3 was found to inhibit the pathway between chorismate and para -aminobenzoic acid (pAba) with a MIC value of 11.3,,M, representing a new example of pAba inhibitor isolated from a natural source. All compounds were not toxic to Candida albicans SC5314 at a concentration up to 100,,M. [source] Apparent growth phase-dependent phosphorylation of malonyl coenzyme A:acyl carrier protein transacylase (MCAT), a major fatty acid synthase II component in Mycobacterium bovis BCGFEMS MICROBIOLOGY LETTERS, Issue 1 2003Indrajit Sinha Abstract Probing protein extracts from exponentially growing and stationary phase cultures of Mycobacterium bovis BCG with anti-phospho amino acid antibodies revealed a 31-kDa anti-phospho threonine antibody-reactive protein specific to growing culture. The corresponding protein was purified via two-dimensional gel electrophoresis and identified via mass spectrometry to be malonyl coenzyme A:acyl carrier protein transacylase (MCAT), a component of the fatty acid biosynthetic pathway. MCAT tagged with histidine reacted with anti-phospho threonine antibody and was positive in an in-gel chemical assay for phospho proteins. Analysis of the growth phase dependence of MCAT-His phosphorylation and protein levels showed that phosphorylated MCAT-His can be detected only in growing culture. In contrast, MCAT-His protein level was growth phase-independent. These results suggest that MCAT may be a substrate of a protein kinase and phosphatase, and that aspects of fatty acid synthesis in tubercle bacilli are regulated by protein phosphorylation. [source] Increasing the sialylation of therapeutic glycoproteins: The potential of the sialic acid biosynthetic pathwayJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2009Kaya Bork Abstract The number of therapeutic proteins has increased dramatically over the past years and most of the therapeutic proteins in the market today are glycoproteins. Usually, recombinant glycoproteins are produced in mammalian cell lines, such as Chinese-hamster-ovary-cells to obtain mammalian-type of glycosylation. The terminal monosaccharide of N-linked complex glycans is typically occupied by sialic acid. Presence of this sialic acid affects absorption, serum half-life, and clearance from the serum, as well as the physical, chemical and immunogenic properties of the respective glycoprotein. From a manufacturing perspective, the degree of sialylation is crucial since sialylation varies the function of the product. In addition, insufficient or inconsistent sialylation is also a major problem for the process consistency. Sialylation of over-expressed glycoproteins in all mammalian cell lines commonly used in biotechnology for the production of therapeutic glycoproteins is incomplete and there is a need for strategies leading to homogenous, naturally sialylated glycoproteins. This review will shortly summarize the biosynthesis of sialic acids and describe some recent strategies to increase or modify sialylation of specific therapeutic glycoproteins. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3499,3508, 2009 [source] PLASTID FATTY ACID BIOSYNTHESIS IN THE DIATOMS NITZSCHIA ALBA AND NITZSCHIA LAEVISJOURNAL OF PHYCOLOGY, Issue 2000K.M. McGinnis The role of the plastid in fatty acid biosynthesis in the non-photosynthetic diatom Nitzschia alba was studied and compared to that in the photosynthetic, closely related Nitzschia laevis. Transmission electron microscopy was used to analyze structural features of the plastid that may be relevant to biochemical function. Typical of a photosynthetic diatom, N. laevis had a chloroplast envelope composed of four membranes, and had abundant chloroplast ribosomes. The leucoplast of N. alba also had a multi-membrane envelope, chloroplast ribosomes, and a genome that encodes plastid specific proteins. This suggested that the plastid of N. alba may still possess the biochemical functions of the chloroplast, aside from photosynthesis. To determine whether plastidial fatty acid biosynthesis occurred in N. alba, the response of the two diatoms to the compound thiolactomycin was compared. Thiolactomycin has been shown to effect keto-acyl-ACP-synthases, and specifically inhibits the plastidial fatty acid biosynthetic pathway. While growth of N. alba was not impacted by thiolactomycin as in N. laevis, neutral lipid accumulation and fatty acid composition was impacted by thiolactomycin in both organisms. These findings suggest that the plastidial fatty acid biosynthetic pathway does exist in the leucoplast of N. alba, although it lacks photosynthetic capacity. [source] Role of WRINKLED1 in the transcriptional regulation of glycolytic and fatty acid biosynthetic genes in ArabidopsisTHE PLANT JOURNAL, Issue 6 2009Sébastien Baud Summary The WRINKLED1 (WRI1) protein is an important regulator of oil accumulation in maturing Arabidopsis seeds. WRI1 is a member of a plant-specific family of transcription factors (AP2/EREBP) that share either one or two copies of a DNA-binding domain called the AP2 domain. Here, it is shown that WRI1 acts as a transcriptional enhancer of genes involved in carbon metabolism in transgenic seeds overexpressing this transcription factor. PKp-,1 and BCCP2, two genes encoding enzymes of the glycolysis and fatty acid biosynthetic pathway, respectively, have been chosen to investigate the regulatory action exerted by WRI1 over these pathways. Using the reporter gene uidA, it was possible to demonstrate in planta that WRI1 regulates the activity of both PKp-,1 and BCCP2 promoters. Electrophoretic mobility-shift assays and yeast one-hybrid experiments showed that WRI1 was able to interact with the BCCP2 promoter. To further elucidate the regulatory mechanism controlling the transcription of these genes, functional dissections of PKp-,1 and BCCP2 promoters were performed. Two enhancers, of 54 and 79 bp, respectively, have thus been isolated that are essential to direct the activity of these promoters in oil-accumulating tissues of the embryo. A consensus site is present in these enhancers as well as in other putative target promoters of WRI1. Loss of this consensus sequence in the BCPP2 promoter decreases both the strength of the interaction between WRI1 and this promoter in yeast and the activity of the promoter in planta. [source] Plant-based corosolic acid: Future anti-diabetic drug?BIOTECHNOLOGY JOURNAL, Issue 12 2009Ganapathy Sivakumar Abstract Diabetes is one of the nation's most prevalent, debilitating and costly diseases. For diabetes, frequent insulin treatment is very expensive and may increase anti-insulin antibody production, which may cause unwanted side effects. Corosolic acid may also have some efficacy in the treatment of diabetes, but without induction of anti-insulin antibodies. Recently, corosolic acid from Lagerstroemia speciosa L. leaf extracts has been reported to act via an indirect mechanism (unlike insulin) in animal experiments. The insulin-complementary anti-diabetic therapeutic value observed in these Japanese preliminary clinical trials has led to renewed interest in the biosynthesis of this compound. So far, there has been no clear evidence for a corosolic acid biosynthetic pathway in plants. This article provides possible roles of corosolic acid and hypothetical information on the biosynthetic pathway in plants. [source] Dynamics of genome evolution in facultative symbionts of aphidsENVIRONMENTAL MICROBIOLOGY, Issue 8 2010Patrick H. Degnan Summary Aphids are sap-feeding insects that host a range of bacterial endosymbionts including the obligate, nutritional mutualist Buchnera plus several bacteria that are not required for host survival. Among the latter, ,Candidatus Regiella insecticola' and ,Candidatus Hamiltonella defensa' are found in pea aphids and other hosts and have been shown to protect aphids from natural enemies. We have sequenced almost the entire genome of R. insecticola (2.07 Mbp) and compared it with the recently published genome of H. defensa (2.11 Mbp). Despite being sister species the two genomes are highly rearranged and the genomes only have ,55% of genes in common. The functions encoded by the shared genes imply that the bacteria have similar metabolic capabilities, including only two essential amino acid biosynthetic pathways and active uptake mechanisms for the remaining eight, and similar capacities for host cell toxicity and invasion (type 3 secretion systems and RTX toxins). These observations, combined with high sequence divergence of orthologues, strongly suggest an ancient divergence after establishment of a symbiotic lifestyle. The divergence in gene sets and in genome architecture implies a history of rampant recombination and gene inactivation and the ongoing integration of mobile DNA (insertion sequence elements, prophage and plasmids). [source] The role of the yeast plasma membrane SPS nutrient sensor in the metabolic response to extracellular amino acidsMOLECULAR MICROBIOLOGY, Issue 1 2001Hanna Forsberg In response to discrete environmental cues, Saccharomyces cerevisiae cells adjust patterns of gene expression and protein activity to optimize metabolism. Nutrient-sensing systems situated in the plasma membrane (PM) of yeast have only recently been discovered. Ssy1p is one of three identified components of the Ssy1p,Ptr3p,Ssy5 (SPS) sensor of extracellular amino acids. SPS sensor-initiated signals are known to modulate the expression of a number of amino acid and peptide transporter genes (i.e. AGP1, BAP2, BAP3, DIP5, GAP1, GNP1, TAT1, TAT2 and PTR2) and arginase (CAR1). To obtain a better understanding of how cells adjust metabolism in response to extracellular amino acids in the environment and to assess the consequences of loss of amino acid sensor function, we investigated the effects of leucine addition to wild-type and ssy1 null mutant cells using genome-wide transcription profile analysis. Our results indicate that the previously identified genes represent only a subset of the full spectrum of Ssy1p-dependent genes. The expression of several genes encoding enzymes in amino acid biosynthetic pathways, including the branched-chain, lysine and arginine, and the sulphur amino acid biosynthetic pathways, are modulated by Ssy1p. Additionally, the proper transcription of several nitrogen-regulated genes, including NIL1 and DAL80, encoding well-studied GATA transcription factors, is dependent upon Ssy1p. Finally, several genes were identified that require Ssy1p for wild-type expression independently of amino acid addition. These findings demonstrate that yeast cells require the SPS amino acid sensor component, Ssy1p, to adjust diverse cellular metabolic processes properly. [source] The serine palmitoyltransferase from Sphingomonas wittichii RW1: An interesting link to an unusual acyl carrier proteinBIOPOLYMERS, Issue 9 2010Marine C. C. Raman Abstract Serine palmitoyltransferase (SPT) catalyses the first step in the de novo biosynthesis of sphingolipids (SLs). It uses a decarboxylative Claisen-like condensation reaction to couple L -serine with palmitoyl-CoA to generate a long-chain base product, 3-ketodihydrosphingosine. SLs are produced by mammals, plants, yeast, and some bacteria, and we have exploited the complete genome sequence of Sphingomonas wittichii to begin a complete analysis of bacterial sphingolipid biosynthesis. Here, we describe the enzymatic characterization of the SPT from this organism and present its high-resolution x-ray structure. Moreover, we identified an open reading frame with high sequence homology to acyl carrier proteins (ACPs) that are common to fatty acid biosynthetic pathways. This small protein was co-expressed with the SPT and we isolated and characterised the apo- and holo-forms of the ACP. Our studies suggest a link between fatty acid and sphingolipid metabolism. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 811,822, 2010. [source] Study of stationary phase metabolism via isotopomer analysis of amino acids from an isolated proteinBIOTECHNOLOGY PROGRESS, Issue 1 2010Afshan S. Shaikh Abstract Microbial production of many commercially important secondary metabolites occurs during stationary phase, and methods to measure metabolic flux during this growth phase would be valuable. Metabolic flux analysis is often based on isotopomer information from proteinogenic amino acids. As such, flux analysis primarily reflects the metabolism pertinent to the growth phase during which most proteins are synthesized. To investigate central metabolism and amino acids synthesis activity during stationary phase, addition of fully 13C-labeled glucose followed by induction of green fluorescent protein (GFP) expression during stationary phase was used. Our results indicate that Escherichia coli was able to produce new proteins (i.e., GFP) in the stationary phase, and the amino acids in GFP were mostly from degraded proteins synthesized during the exponential growth phase. Among amino acid biosynthetic pathways, only those for serine, alanine, glutamate/glutamine, and aspartate/asparagine had significant activity during the stationary phase. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | |||||||||||||