Search results for "nuclei"
showing 10 items of 1273 documents
The complete mitochondrial genome of Bactrocera biguttula (Bezzi) (Diptera: Tephritidae) and phylogenetic relationships with other Dacini
2018
Bactrocera biguttula is an African olive fruit fly that does not attack cultivated olives but rather develops in the fruits of wild species of Olea and Noronhia. The complete mitochondrial genome of an individual specimen was characterized in comparison to other Bactrocera. The phylogenetic relationships of B. biguttula with other Dacini were investigated, with special focus on B. oleae, an agricultural pest known to attack cultivated and wild olives. The sequence had a total length of 15,829 bp, and included the typical features of insect mitogenomes, similarly to the other Bactrocera analysed. Start codons included ATG, ATC, ATT, and TCG (in COI). The majority of stop codons (TAA) were fu…
The mitochondrial genome of fission yeast: inability of all introns to splice autocatalytically, and construction and characterization of an intronle…
1991
In this paper we report the inability of four group I introns in the gene encoding subunit I of cytochrome c oxidase (cox1) and the group II intron in the apocytochrome b gene (cob) to splice autocatalytically. Furthermore we present the characterization of the first cox1 intron in the mutator strain anar-14 and the construction and characterization of strains with intronless mitochondrial genomes. We provide evidence that removal of introns at the DNA level (termed DNA splicing) is dependent on an active RNA maturase. Finally we demonstrate that the absence of introns does not abolish homologous mitochondrial recombination.
Mitochondrial simple sequenze repeats and 12s – rRNA gene reveal two distinct lineages of Crocidura russula (Mammalia, Sorcidae)
2004
A short segment (135 bp) of the control region and a partial sequence (394 bp) of the 12S-rRNA gene in the mitochondrial DNA of Crocidura russula were analyzed in order to test a previous hypothesis regarding the presence of a gene flow disruption in northern Africa. This breakpoint would have separated northeast-African C. russula populations from the European (plus the northwest-African) populations. The analysis was carried out on specimens from Tunisia (C. r. cf agilis), Sardinia (C. r. ichnusae), and Pantelleria (C. r. cossyrensis), and on C. r. russula from Spain and Belgium. Two C. russula lineages were identified; they both shared R2 tandem repeated motifs of the same length (12 bp)…
Pharmacophore Models Derived from Molecular Dynamics Simulations of Protein-Ligand Complexes: A Case Study
2018
A single, merged pharmacophore hypothesis is derived combining 2000 pharmacophore models obtained during a 20 ns molecular dynamics simulation of a protein-ligand complex with one pharmacophore model derived from the initial PDB structure. This merged pharmacophore model contains all features that are present during the simulation and statistical information about the dynamics of the pharmacophore features. Based on the dynamics of the pharmacophore features we derive two distinctive feature patterns resulting in two different pharmacophore models for the analyzed system – the first model consists of features that are obtained from the PDB structure and the second uses two features that ca…
The Hammerhead Ribozyme: A Long History for a Short RNA
2017
Small nucleolytic ribozymes are a family of naturally occurring RNA motifs that catalyse a self-transesterification reaction in a highly sequence-specific manner. The hammerhead ribozyme was the first reported and the most extensively studied member of this family. However, and despite intense biochemical and structural research for three decades since its discovery, the history of this model ribozyme seems to be far from finished. The hammerhead ribozyme has been regarded as a biological oddity typical of small circular RNA pathogens of plants. More recently, numerous and new variations of this ribozyme have been found to inhabit the genomes of organisms from all life kingdoms, although th…
All-atom simulations disentangle the functional dynamics underlying gene maturation in the intron lariat spliceosome
2018
The spliceosome (SPL) is a majestic macromolecular machinery composed of five small nuclear RNAs and hundreds of proteins. SPL removes noncoding introns from precursor messenger RNAs (pre-mRNAs) and ligates coding exons, giving rise to functional mRNAs. Building on the first SPL structure solved at near–atomic-level resolution, here we elucidate the functional dynamics of the intron lariat spliceosome (ILS) complex through multi-microsecond-long molecular-dynamics simulations of ∼1,000,000 atoms models. The ILS essential dynamics unveils (i) the leading role of the Spp42 protein, which heads the gene maturation by tuning the motions of distinct SPL components, and (ii) the critical particip…
Correction to ‘Secondary structure determination of conserved SARS-CoV-2 RNA elements by NMR spectroscopy’
2021
The current pandemic situation caused by the Betacoronavirus SARS-CoV-2 (SCoV2) highlights the need for coordinated research to combat COVID-19. A particularly important aspect is the development of medication. In addition to viral proteins, structured RNA elements represent a potent alternative as drug targets. The search for drugs that target RNA requires their high-resolution structural characterization. Using nuclear magnetic resonance (NMR) spectroscopy, a worldwide consortium of NMR researchers aims to characterize potential RNA drug targets of SCoV2. Here, we report the characterization of 15 conserved RNA elements located at the 5' end, the ribosomal frameshift segment and the 3'-un…
Advances in DNA-ligands with groove binding, intercalating and/or alkylating activity: chemistry, DNA-binding and biology.
2005
It is known that DNA is a well-characterized intracellular target but its size and sequential characteristics make it an elusive target for selective drug action. Binding of low molecular weight ligands to DNA causes a variety of significant biological responses. In this context the main consideration is given to recent developments in DNA sequence selective binding agents bearing conjugated effectors because of their potential application in treatment of cancers, in diagnosis as well as in molecular biology. In the present review recent results about analogues of netropsins, distamycin A and of some lexitropsins and combilexins or related hybrid molecules with sequence reading, intercalati…
A novel bio-orthogonal cross-linker for improved protein/protein interaction analysis
2015
International audience; The variety of protein cross-linkers developed in recent years illustrates the current requirement for efficient reagents optimized for mass spectrometry (MS) analysis. To date, the most widely used strategy relies on commercial cross-linkers that bear an isotopically labeled tag and N-hydroxysuccinimid-ester (NHS-ester) moieties. Moreover, an enrichment step using liquid chromatography is usually performed after enzymatic digestion of the cross-linked proteins. Unfortunately, this approach suffers from several limitations. First, it requires large amounts of proteins. Second, NHS-ester cross-linkers are poorly efficient because of their fast hydrolysis in water. Fin…
Assessing the Differential Affinity of Small Molecules for Noncanonical DNA Structures
2012
The targeting of higher-order DNA structures has been thoroughly developed with G-quadruplex DNA but not with other structures like branched DNA (also known as DNA junctions). Because these alternative higher-order DNA architectures might be of high biological relevance, we implemented a high-throughput version of the FRET melting assay that enabled us to map the interactions of a candidate with four different DNA structures (duplex- and quadruplex DNA, three- and four-way junctions) in a rapid and reliable manner. We also introduce a novel index, the BONDS (branched and other noncanonical DNA selectivity) index, to conveniently quantify this differential affinity.