Search results for " Amin"

Inducible Genetic Code Expansion in Eukaryotes

2020

Abstract Genetic code expansion (GCE) is a versatile tool to site‐specifically incorporate a noncanonical amino acid (ncAA) into a protein, for example, to perform fluorescent labeling inside living cells. To this end, an orthogonal aminoacyl‐tRNA‐synthetase/tRNA (RS/tRNA) pair is used to insert the ncAA in response to an amber stop codon in the protein of interest. One of the drawbacks of this system is that, in order to achieve maximum efficiency, high levels of the orthogonal tRNA are required, and this could interfere with host cell functionality. To minimize the adverse effects on the host, we have developed an inducible GCE system that enables us to switch on tRNA or RS expression whe…

Determinazione di componenti della vernice e della colla del contrabbasso “Panormo” di Vincenzo Trusiano

2007

Sorting signals in the cytosolic tail of membrane proteins involved in the interaction with plant ARF1 and coatomer.

2004

Summary In mammals and yeast, a cytosolic dilysine motif is critical for endoplasmic reticulum (ER) localization of type I membrane proteins. Retrograde transport of type I membrane proteins containing dilysine motifs at their cytoplasmic carboxy (C)-terminal tail involves the interaction of these motifs with the COPI coat. The C-terminal dilysine motif has also been shown to confer ER localization to type I membrane proteins in plant cells. Using in vitro binding assays, we have analyzed sorting motifs in the cytosolic tail of membrane proteins, which may be involved in the interaction with components of the COPI coat in plant cells. We show that a dilysine motif in the −3,−4 position (rel…

17O NMR and molecular mechanical studies of arylmethylenemalonaldehydes

1990

The 17O NMR spectra of six different arylmethylenemalonaldehydes were measured for various solvents and temperatures. The 17O NMR chemical shifts and line widths of the carbonyl oxygens of the malonaldehyde fragment show a clear variation in the series of monoaryl compounds studied. The differences between the 17O NMR chemical shifts of the formyl oxygens correlate well with two conformationally dependent 1H–1H and 1H–13C coupling constants for the same compounds. Molecular mechanical calculations were also performed in order to relate the present data with the conformational preferences of the malonaldehyde fragment of the arylmethylenemalonaldehydes.

Metabolic relation of cyanobacteria to aromatic compounds

2018

Cyanobacteria, also known as blue-green (micro)algae, are able to sustain many types of chemical stress because of metabolic adaptations that allow them to survive and successfully compete in a variety of ecosystems, including polluted ones. As photoautotrophic bacteria, these microorganisms synthesize aromatic amino acids, which are precursors for a large variety of substances that contain aromatic ring(s) and that are naturally formed in the cells of these organisms. Hence, the transformation of aromatic secondary metabolites by cyanobacteria is the result of the possession of a suitable “enzymatic apparatus” to carry out the biosynthesis of these compounds according to cellular requireme…

2'-O-methyl-5-formylcytidine (f5Cm), a new modified nucleotide at the 'wobble' of two cytoplasmic tRNAs Leu (NAA) from bovine liver.

1996

The nucleotide analysis of a cytoplasmic tRNA(Leu) isolated from bovine liver revealed the presence of an unknown modified nucleotide N. The corresponding N nucleoside was isolated by different enzymatic and chromatographic protocols from a partially purified preparation of this tRNA(Leu). Its chemical characterization was determined from its chromatographic properties, UV-absorption spectroscopy and mass spectrometric measurements, as well as from those of the borohydride reduced N nucleoside and its etheno-trimethylsilyl derivative. The structure of N was established as 2'-O-methyl-5-formylcytidine (f5CM), and its reduced derivative as 2'-O-methyl-5-hydroxy-methylcytidine (om5Cm). By sequ…

Establishment and functional validation of a structural homology model for human DNA methyltransferase 1

2003

Changes in DNA methylation patterns play an important role in tumorigenesis. The DNA methyltransferase 1 (DNMT1) protein represents a major DNA methyltransferase activity in human cells and is therefore a prominent target for experimental cancer therapies. However, there are only few available inhibitors and their high toxicity and low specificity have so far precluded their broad use in chemotherapy. Based on the strong conservation of catalytic DNA methyltransferase domains we have used a homology modeling approach to determine the three-dimensional structure of the DNMT1 catalytic domain. Our results suggest an overall structural conservation with other DNA methyltransferases but also in…

Induction of DNA strand breaks and expression of HSP70 and GRP78 homolog by cadmium in the marine sponge Suberites domuncula

1998

The marine sponge Suberites domuncula was used as a bioindicator to study the effects of cadmium on the occurrence of DNA strand breakage and on the induction of the expression of the stress biomarkers, heat shock protein 70 (HSP70) and glucose-regulated protein 78 (GRP78) homolog. The cDNA encoding GRP78 homolog from S. domuncula was isolated and characterized. The GRP78 cDNA has a length of 2.1 kb and displays characteristic features of the HSP70 family ; it encodes an aa sequence of M-r 72, 000. Exposure of S. domuncula to 1 mg/L of cadmium chloride for 24 h caused a strong(16.6-fold) increase in cadmium content to 7.7 mu g/g wet weight of sponge tissue ; after an incubation period of 6 …

Selection of amine-oxidizing dairy lactic acid bacteria and identification of the enzyme and gene involved in the decrease of biogenic amines

2016

ABSTRACT Accumulation of biogenic amines (BAs) in cheese and other foods is a matter of public health concern. The aim of this study was to identify the enzyme activities responsible for BA degradation in lactic acid bacteria which were previously isolated from traditional Sicilian and Apulian cheeses. The selected strains would control the concentration of BAs during cheese manufacture. First, 431 isolates not showing genes encoding the decarboxylases responsible for BA formation were selected using PCR-based methods. Ninety-four out of the 431 isolates degraded BAs (2-phenylethylamine, cadaverine, histamine, putrescine, spermine, spermidine, tyramine, or tryptamine) during cultivation on …

Comprehensive DNA methylation analysis of the Aedes aegypti genome

2016

AbstractAedes aegypti mosquitoes are important vectors of viral diseases. Mosquito host factors play key roles in virus control and it has been suggested that dengue virus replication is regulated by Dnmt2-mediated DNA methylation. However, recent studies have shown that Dnmt2 is a tRNA methyltransferase and that Dnmt2-dependent methylomes lack defined DNA methylation patterns, thus necessitating a systematic re-evaluation of the mosquito genome methylation status. We have now searched the Ae. aegypti genome for candidate DNA modification enzymes. This failed to reveal any known (cytosine-5) DNA methyltransferases, but identified homologues for the Dnmt2 tRNA methyltransferase, the Mettl4 (…