70 research outputs found
Mechanical response of plectonemic DNA: an analytical solution
We consider an elastic rod model for twisted DNA in the plectonemic regime.
The molecule is treated as an impenetrable tube with an effective, adjustable
radius. The model is solved analytically and we derive formulas for the contact
pressure, twisting moment and geometrical parameters of the supercoiled region.
We apply our model to magnetic tweezer experiments of a DNA molecule subjected
to a tensile force and a torque, and extract mechanical and geometrical
quantities from the linear part of the experimental response curve. These
reconstructed values are derived in a self-contained manner, and are found to
be consistent with those available in the literature.Comment: 14 pages, 4 figure
Reconstruction of bacterial transcription-coupled repair at single-molecule resolution
International audienc
Reconstruction of bacterial transcription-coupled repair at single-molecule resolution
Fluorescent Lifetime Trajectories of a Single Fluorophore Reveal Reaction Intermediates During Transcription Initiation
The positions of TFIIF and TFIIE in the RNA polymerase II transcription preinitiation complex.
We incorporated the non-natural photoreactive amino acid p-benzoyl-L-phenylalanine (Bpa) into the RNA polymerase II (Pol II) surface surrounding the central cleft formed by the Rpb1 and Rpb2 subunits. Photo-cross-linking of preinitiation complexes (PICs) with these Pol II derivatives and hydroxyl-radical cleavage assays revealed that the TFIIF dimerization domain interacts with the Rpb2 lobe and protrusion domains adjacent to Rpb9, while TFIIE cross-links to the Rpb1 clamp domain on the opposite side of the Pol II central cleft. Mutations in the Rpb2 lobe and protrusion domains alter both Pol II-TFIIF binding and the transcription start site, a phenotype associated with mutations in TFIIF, Rpb9 and TFIIB. Together with previous biochemical and structural studies, these findings illuminate the structural organization of the PIC and the network of protein-protein interactions involved in transcription start site selection
Bacterial replication, transcription and translation: mechanistic insights from single-molecule biochemical studies
EPIDEMIC SITUATION AND TREATMENT PROSPECTS OF MULTIPLE RESISTANT TUBERCULOSIS IN KANTY-MANSIYSKY AUTONOMOUS REGION
The article describes the changes in the main tuberculosis rates in Khanty-Mansiysky Autonomous Region for the last 10 years. The main areas requiring major efforts and bottlenecks in tuberculosis control are highlighted, and the results achieved in the treatment of multiple drug resistant tuberculosis in this Russian region are presented. The article presents preliminary analysis of treatment efficiency of multiple drug resistant tuberculosis and changes in the epidemics of this most dangerous form of the disease given the introduction and active use of a new generation of anti-tuberculosis drugs
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