Search results for "acetylation"
showing 10 items of 140 documents
Structural determination of the lipo-chitin oligosaccharide nodulation signals produced by Rhizobium giardinii bv. giardinii H152
2003
Abstract Rhizobium giardinii bv. giardinii is a microsymbiont of plants of the genus Phaseolus and produces extracellular signal molecules that are able to induce deformation of root hairs and nodule organogenesis. We report here the structures of seven lipochitooligosaccharide (LCO) signal molecules secreted by R. giardinii bv. giardinii H152. Six of them are pentamers of GlcNAc carrying C 16:0 , C 18:0 , C 20:0 and C 18:1 fatty acyl chains on the non-reducing terminal residue. Four are sulfated at C-6 of the reducing terminal residue and one is acetylated in the same position. Six of them are N -methylated on the non-reducing GlcN residue and all the nodulation factors are carbamoylated o…
Liver-specific methionine adenosyltransferase MAT1A gene expression is associated with a specific pattern of promoter methylation and histone acetyla…
2000
Methionine adenosyltransferase (MAT) is the enzyme that catalyzes the synthesis of S-adenosylmethionine (AdoMet), the main donor of methyl groups in the cell. In mammals MAT is the product of two genes, MAT1A and MAT2A. MAT1A is expressed only in the mature liver whereas fetal hepatocytes, extrahepatic tissues and liver cancer cells express MAT2A. The mechanisms behind the tissue and differentiation state specific MAT1A expression are not known. In the present work we examined MAT1A promoter methylation status by means of methylation sensitive restriction enzyme analysis. Our data indicate that MAT1A promoter is hypomethylated in liver and hypermethylated in kidney and fetal rat hepatocytes…
Hepatocyte growth factor induces MAT2A expression and histone acetylation in rat hepatocytes: role in liver regeneration 1
2001
SPECIFIC AIMSWe have studied the molecular mechanisms and mediators behind the induction of methionine adenosyltransferase 2 A (MAT2A) gene expression in the regenerating rat liver after partial he...
ChemInform Abstract: Photochemistry of 7-Acetoxybenzopyran Derivatives. Synthesis of Eupatoriochromene and Encecalin.
1990
Abstract The photolysis of the 7-acetoxybenzopyran derivatives 1a-5a has been carried out. Chromene 1a was found to undergo extensive photopolymerization. Chromanone 2a underwent a rather inefficient photo-Fries rearrangement to the 6 - and 8 - acetyl derivatives 2b and 2c . Diacetoxychromene 3a gave the unsaturated ketone 8 as the main product, besides its deacetylation analogue 9 and chromanone 11 . Diacetoxychroman 4a afforded a mixture of four C-acetyl products: 1b, 1c, 2b and 2c , together with Chromene 1a and chromanone 2a. Finally, irradiation of chroman 5a gave rise to a mixture of the two possible photo-Fries products 5b (43%) and 5c (52%). The mechanistic implications of the above…
Chemistry of detrifluoroacetylativelyin situgenerated fluoro-enolates
2018
This review article comprehensively profiles all literature reports (2015-2018) related to the detrifluoroacetylative in situ generation of fluorine-containing enolates and their reactions with electrophilic reagents. The innovative facets of this unconventional methodology and its synthetic generality for the preparation of fluorine-containing compounds of high medicinal value are highlighted.
In vivo GSH depletion induces c-myc expression by modulation of chromatin protein complexes.
2009
Abstract We hypothesize that glutathione (GSH) fluctuations could have a prominent role in the modulation of c-myc expression through a mechanism affecting chromatin remodeling complexes. This could lead to an open chromatin structure accessible to transcription factors. We studied the in vivo effect of GSH depletion on these complexes bound to the c-myc promoter in the liver of l-buthionine-(S,R)-sulfoximine (BSO)-treated rats. Using chromatin immunoprecipitation we found that 3 h after BSO treatment the repressing complexes Id2 and Sin3A (part of a histone–deacetylase complex) were released from the c-myc promoter. STAT3 was phosphorylated and associated with its coactivator p300 with int…
Crystal structures of O-acetylated 2-acylamino-2-deoxy-d-galactose derivatives
2003
The X-ray structures of 1,3,4,6-tetra-O-acetyl-2-deoxy-alpha-D-galactopyranoside derivatives with four different 2-(acylamino) substituents have been determined with Mo K(alpha) radiation at 123 K. The structure of the 2-acetylamino derivative and of its acyl-homologs with a 2-(propanoylamino)-, 2-(butanoylamino)-, and 2-(2-methyl-propanoylamino)-group crystallized in the monoclinic space group C2. The pyranose unit of all compounds has the usual 4C(1) shape. The different orientations of the 6-O-acetyl-groups are discussed. Conformations of the acylamino-group are compared to those found in the crystal structure of N-acetyl-alpha-D-galactosamine.
HAT1 and HAT2 Proteins Are Components of a Yeast Nuclear Histone Acetyltransferase Enzyme Specific for Free Histone H4
1998
We have analyzed the histone acetyltransferase enzymes obtained from a series of yeast hat1, hat2, and gcn5 single mutants and hat1,hat2 and hat1,gcn5 double mutants. Extracts prepared from both hat1 and hat2 mutant strains specifically lack the following two histone acetyltransferase activities: the well known cytoplasmic type B enzyme and a free histone H4-specific histone acetyltransferase located in the nucleus. The catalytic subunits of both cytoplasmic and nuclear enzymes have identical molecular masses (42 kDa), the same as that of HAT1. However, the cytoplasmic complex has a molecular mass (150 kDa) greater than that of the nuclear complex (110 kDa). The possible functions of HAT1 a…
On the ubiquitous presence of histone acetyltransferase B in eukaryotes
1985
AbstractHistone acetyltransferase B activity has been found in pea (Pisun sativum) seedlings. The enzyme has been partially purified and it has been found that it is highly specific for H4. The results confirm that histone acetyltransferase B occurs in 3 eukaryotic kingdoms.
Plant Responses to Abiotic Stress Regulated by Histone Deacetylases
2017
In eukaryotic cells, histone acetylation and deacetylation play an important role in the regulation of gene expression. Histone acetylation levels are modulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Recent studies indicate that HDACs play essential roles in the regulation of gene expression in plant response to environmental stress. In this review, we discussed the recent advance regarding the plant HDACs and their functions in the regulation of abiotic stress responses. The role of HDACs in autophagy was also discussed.