Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.2.1.1 (ACS)
 78,556 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acetyl-coenzyme A synthetase (ACS; EC 6.2.1.1) from some plectomycete fungi is possibly involved in an accessory step of penicillin biosynthesis, in addition to its role in primary metabolism. We present the characterisation of the gene encoding this enzyme in Penicillium chrysogenum, which we designated acuA. Sequencing of genomic and cDNA clones showed that the coding region was interrupted by five introns, located at the same positions as those present in the Aspergillus nidulans homologue. This supports the possibility that the gene acquired its definitive mosaic organisation before the Penicillium/Aspergillus divergence. The mature transcript encodes a polypeptide with an M(r) of 74,287 which is 89.4% identical to its A. nidulans counterpart.
 ...
PMID:Characterisation of the gene encoding acetyl-CoA synthetase in Penicillium chrysogenum: conservation of intron position in plectomycetes. 810 29

The nucleotide sequences of two highly homologous 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS; EC 4.4.1.14)-encoding genes, ACS1 and ACS3, of Arabidopsis thaliana (At) have been determined. The sequence analysis shows that ACS3 is a pseudogene representing a truncated version of ACS1. The missing region of ACS3 corresponding to the fourth exon of ACS1 has been shown by Southern analysis to be absent in the At genome. The chromosomal locations of the five members of the At ACS multigene family have been determined. The results show that each family member resides on a different chromosome. This observation suggests that the ACS3 pseudogene originated by a partial inter-chromosomal gene duplication. The ACS1 polypeptide contains all the conserved and characteristic domains found in the ACC synthase isoenzymes from various plant species, but is unable to express ACS activity in Escherichia coli and yeast. The predicted amino-acid sequence of ACS1 is missing the highly conserved tripeptide, Thr-Asn-Pro (TNP), between Ile204 and Ser205. Introduction of TNP into ACS1 restores the ACS activity, whereas its removal from the enzymatically active ACS2 results in a loss of activity. The results suggest that TNP is crucial for expression of ACS activity in E. coli.
 ...
PMID:Characterization of two members (ACS1 and ACS3) of the 1-aminocyclopropane-1-carboxylate synthase gene family of Arabidopsis thaliana. 856 72

We have mapped a region of about 33 kb which includes the transcription unit of the C-3 DNA puff gene of Rhynchosciara americana. The C-3 TU and a region extending approximately 800 bp upstream of the C-3 promoter were characterized. The TU is composed of three exons and produces a 1.1-kb mRNA whose level in salivary glands increases with the expansion of the C-3 puff. The C-3 messenger appears to undergo rapid deadenylation resulting in an RNA of about 0.95 kb which can still be observed in gland cells 15 h after the puff has regressed. The 1.1-kb mRNA codes for a 32.4-kDa, predominantly alpha-helical polypeptide with three conserved parallel coiled-coil stretches. The aa composition and structure of this polypeptide suggests that it is secreted and contributes to the formation of the cocoon in which the larvae pupate. The region upstream of the promoter contains several A-rich sequences with similarity to the ACS of yeast which might have a role in the initiation of replication/amplification.
 ...
PMID:Molecular characterization of the C-3 DNA puff gene of Rhynchosciara americana. 925 73

To identify transcriptionally regulated mediators associated with the cell cycle, we adopted the differential mRNA display technique for cell cultures of Tetrahymena pyriformis synchronized by cyclic heat treatment. One cDNA fragment that was expressed differently during synchronous cell division had a greatly decreased expression at 30 min after the end of heat treatment (EHT). Using this fragment as a probe, we isolated the full-length cDNA for T. pyriformis acetyl-CoA synthetase (TpAcs) which encodes a 651 amino acid polypeptide with a predicted molecular mass of 72.8 kDa. The deduced amino acid sequence of T. pyriformis ACS shows 42% sequence identity compared with that of Lysobacter sp. acetyl-CoA synthetase (ACS), an enzyme which catalyses the formation of acetyl-CoA from acetate via an acetyl-adenylate intermediate. The deduced sequence is also 41% and 40% identical compared with those of Pseudomonas putida and Coprinus cinereus ACS, respectively. The deduced sequence of T. pyriformis ACS also shares similar characteristics of the conserved motifs I and II in the ACS family. To further investigate the actions of the gene encoding this enzyme, mRNA expression was determined during the course of synchronized cell division in T. pyriformis. Northern blot results show that the mRNA level was dramatically decreased at 30 min after EHT prior to entering synchronous cell division (which occurs 75 min after EHT), suggesting that mRNA expression of the TpAcs was associated with the cell cycle and that the down-regulated expression of TpAcs at 30 min after EHT would be required for the initiation of the oncoming synchronous cell division in T. pyriformis.
 ...
PMID:Molecular cloning and cell-cycle-dependent expression of the acetyl-CoA synthetase gene in Tetrahymena cells. 1051 Mar 17

Diurnal change in the temperature below or above 12.5 degrees C hastens the degreening of citrus peel and elicits the phytohormone ethylene production in citrus fruit. Ethylene triggers the degradation of chlorophyll and synthesis of carotenoids in citrus peel. To investigate if ethylene is required for the degreening of citrus peel elicited by low temperatures, we studied the chilling-regulated gene expression of ACC synthase, one of the key enzymes catalyzing ethylene biosynthesis. We isolated and characterized a chilling-inducible 1-aminocyclopropane-1-carboxylate synthase (ACC synthase) gene, CS-ACS1, and a chilling-repressible gene, CS-ACS2, from citrus peel. The CS-ACS1 transcript 1.7 kb in length encodes a polypeptide of 483 amino acids (Mr 54,115, pI 6.63), whereas the CS-ACS2 transcript of 1.8 kb encodes a polypeptide of 477 amino acids (Mr 53,291, pI 6.72). Both genes showed a rapid but transient induction (within 2.4 h) of transcripts upon rewarming after the chilling (4 degrees C) treatment. After 24 h of incubation at room temperature, CS-ACS1 mRNA diminished to an undetectable level, whereas the CS-ACS2 mRNA regained its basal level of expression attained prior to the chilling treatment. Chilling-induced ethylene production and ACC accumulation were also observed upon rewarming. Both genes were also induced by the wound stress (excision). The protein synthesis inhibitor cycloheximide super-enhances the accumulation of both ACS transcripts at room temperature. Molecular analysis of the 3.3 kb genomic DNA of CS-ACS1 revealed that this gene consists of three introns and four exons. The intron 3 is exceptionally large ( 1.2 kb) and shares significant homology with mitochondrial DNA, supporting the intron-late theory.
 ...
PMID:Identification of two chilling-regulated 1-aminocyclopropane-1-carboxylate synthase genes from citrus (Citrus sinensis Osbeck) fruit. 1064 19

In higher plants, fat-storing seeds utilize storage lipids as a source of energy during germination. To enter the beta-oxidation pathway, fatty acids need to be activated to acyl-coenzyme As (CoAs) by the enzyme acyl-CoA synthetase (ACS; EC 6.2.1.3). Here, we report the characterization of an Arabidopsis cDNA clone encoding for a glyoxysomal acyl-CoA synthetase designated AtLACS6. The cDNA sequence is 2,106 bp long and it encodes a polypeptide of 701 amino acids with a calculated molecular mass of 76,617 D. Analysis of the amino-terminal sequence indicates that acyl-CoA synthetase is synthesized as a larger precursor containing a cleavable amino-terminal presequence so that the mature polypeptide size is 663 amino acids. The presequence shows high similarity to the typical PTS2 (peroxisomal targeting signal 2). The AtLACS6 also shows high amino acid identity to prokaryotic and eukaryotic fatty acyl-CoA synthetases. Immunocytochemical and cell fractionation analyses indicated that the AtLACS6 is localized on glyoxysomal membranes. AtLACS6 was overexpressed in insect cells and purified to near homogeneity. The purified enzyme is particularly active on long-chain fatty acids (C16:0). Results from immunoblot analysis revealed that the expression of both AtLACS6 and beta-oxidation enzymes coincide with fatty acid degradation. These data suggested that AtLACS6 might play a regulatory role both in fatty acid import into glyoxysomes by making a complex with other factors, e.g. PMP70, and in fatty acid beta-oxidation activating the fatty acids.
 ...
PMID:Molecular characterization of an Arabidopsis acyl-coenzyme a synthetase localized on glyoxysomal membranes. 1248 Oct 85

The pyridoxal phosphate-dependent enzyme, 1-aminocyclopropane-1-carboxylate synthase (ACS; EC 4.4.1.14), catalyzes the rate-limiting step in the ethylene biosynthetic pathway in plants. The Arabidopsis genome encodes nine ACS polypeptides that form eight functional (ACS2, ACS4-9, ACS11) and one nonfunctional (ACS1) homodimers. Because the enzyme is a homodimer with shared active sites, the question arises whether the various polypeptides can form functional heterodimers. Intermolecular complementation experiments in Escherichia coli by coexpressing the K278A and Y92A mutants of different polypeptides show that all of them have the capacity to heterodimerize. However, functional heterodimers are formed only among gene family members that belong to one or the other of the two phylogenetic branches. ACS7 is an exception to this rule, which forms functional heterodimers with some members of both branches when it provides the wt K278 residue. ACS1, the nonfunctional polypeptide as a homodimer, can also form functional heterodimers with members of its phylogenetic branch when its partners provide the wt K278 residue. The ACS gene family products can potentially form 45 homo- and heterodimers of which 25 are functional. Bimolecular fluorescence complementation and biochemical coaffinity purification assays show that the inactivity of certain heterodimers is not due to the absence of heterodimerization but rather to structural restraint(s) that prevents the shared active sites from being functional. We propose that functional heterodimerization enhances the isozyme diversity of the ACS gene family and provides physiological versatility by being able to operate in a broad gradient of S-adenosylmethionine concentration in various cells/tissues during plant growth and development. Nonfunctional heterodimerization may also play a regulatory role during the plant life cycle.
 ...
PMID:Heterodimeric interactions among the 1-amino-cyclopropane-1-carboxylate synthase polypeptides encoded by the Arabidopsis gene family. 1498

A gene homologous to Saccharomyces cerevisiae ACS genes, coding for acetyl-CoA synthetase, has been cloned from the yeast Zygosaccharomyces bailii ISA 1307, by using reverse genetic approaches. A probe obtained by PCR amplification from Z. bailii DNA, using primers derived from two conserved regions of yeast ACS proteins, RIGAIHSVVF (ScAcs1p; 210-219) and RVDDVVNVSG (ScAcs1p; 574-583), was used for screening a Z. bailii genomic library. Nine clones with partially overlapping inserts were isolated. The sequenced DNA fragment contains a complete ORF of 2027 bp (ZbACS2) and the deduced polypeptide shares significant homologies with the products of ACS2 genes from S. cerevisiae and Kluyveromyces lactis (81% and 82% identity and 84% and 89% similarity, respectively). Phylogenetic analysis shows that the sequence of Zbacs2 is more closely related to the sequences from Acs2 than to those from Acs1 proteins. Moreover, this analysis revealed that the gene duplication producing Acs1 and Acs2 proteins has occurred in the common ancestor of S. cerevisiae, K. lactis, Candida albicans, C. glabrata and Debaryomyces hansenii lineages. Additionally, the cloned gene allowed growth of S. cerevisiae Scacs2 null mutant, in medium containing glucose as the only carbon and energy source, indicating that it encodes a functional acetyl-CoA synthetase. Also, S. cerevisiae cells expressing ZbACS2 have a shorter lag time, in medium containing glucose (2%, w/v) plus acetic acid (0.1-0.35%, v/v). No differences in cell response to acetic acid stress were detected both by specific growth and death rates. The mode of regulation of ZbACS2 appears to be different from ScACS2 and KlACS2, being subject to repression by a glucose pulse in acetic acid-grown cells.
 ...
PMID:Isolation of an acetyl-CoA synthetase gene (ZbACS2) from Zygosaccharomyces bailii. 1504 92

Mammalian fatty acid synthase (FAS) is a homodimeric, multifunctional polypeptide which comprises two full sets of catalytic subunits that carry out fatty acid synthesis. A recently published X-ray structure of FAS reveals, for the first time, the organization of all active sites involved in acyl chain elongation and provides a structural framework for interpretation of extensive functional studies. Further analysis with techniques capable of providing information about single molecule conformations will eventually provide a more complete understanding of FAS.
ACS Chem Biol 2006 Apr 25
PMID:Mammalian fatty acid synthase: X-ray structure of a molecular assembly line. 1716 58

The formation of amyloid assemblies is associated with major human disorders. Yet no therapeutic agents presently exist to control this process. In a recent paper, a new bacterial system is described that uses a fusion of the Alzheimer's disease beta-amyloid polypeptide to the GFP. The assay detects the formation of small, soluble amyloid intermediates associated with degenerative diseases. This assay allows the researchers to use high-throughput screening methods to find inhibitors of the formation of amyloid assemblies.
ACS Chem Biol 2006 Aug 22
PMID:From green bacteria to human dementia: a novel model for discovering amyloid assembly inhibitors. 1716 24


1 2 3 4 5 6 7 8 9 10 Next >>