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DNA molecular dynamics

Irina N Vasilyeva, Valery N Zinkin, Vladimir G Bespalov
Exposure to either to low-frequency noise or ionizing radiation causes an increase in the number of chromosomal aberrations in the bone marrow cells and the level of low-molecular-weight DNA in the blood plasma of experimental animals. The dynamics of the content of low-molecular-weight DNA increasing after exposure to low-frequency noise and ionizing radiation differs significantly. Both exposures are able to provide a direct damaging effect on DNA.
2016: Advances in Experimental Medicine and Biology
Maryam Ghahremani Nasab, Leila Hassani, Sara Mohammadi Nejad, Davood Norouzi
A DNA enzyme with peroxidase activity is a G-quadruplex-based DNAzyme formed by hemin and G-quadruplex DNA. Activity of peroxide DNAzymes can be influenced by the structure of quadruplex DNA. In this investigation, the interaction of hemin with T30695 G-quadruplex DNA is evaluated. Molecular dynamic simulation indicates that the binding mode of hemin to G-quadruplex DNA is end-stacking, which is consistent with absorption spectroscopy. Based on fluorescence spectroscopy, hemin ejects thiazole orange from bases of four-strand DNA...
October 17, 2016: Journal of Biological Physics
Maelin da Silva, Patricia Barbosa, Roberto F Artoni, Eliana Feldberg
Gymnotidae is a family of electric fish endemic to the Neotropics consisting of 2 genera: Electrophorus and Gymnotus. The genus Gymnotus is widely distributed and is found in all of the major Brazilian river systems. Physical and molecular mapping data for the ribosomal DNA (rDNA) in this genus are still scarce, with its chromosomal location known in only 11 species. As other species of Gymnotus with 2n = 54 chromosomes from the Paraná-Paraguay basin, G. mamiraua was found to have a large number of 5S rDNA sites...
October 18, 2016: Cytogenetic and Genome Research
Joanna J Hoppins, David R Gruber, Heather L Miears, Alexey S Kiryutin, Rustem D Kasymov, Darya V Petrova, Anton V Endutkin, Alexander V Popov, Alexandra V Yurkovskaya, Stanislav O Fedechkin, Jacob A Brockerman, Dmitry O Zharkov, Serge L Smirnov
8-oxoguanine is one of the most abundant and impactful oxidative DNA lesions. However, the reasons underlying its effects, especially those not directly explained by the altered base pairing ability, are poorly understood. We report the effect of the lesion on the action of EcoRI, a widely used restriction endonuclease. Introduction of 8-oxoguanine inside, or adjacent to, the GAATTC recognition site embedded within the Drew-Dickerson dodecamer sequence notably reduced the EcoRI activity. Solution NMR revealed that 8-oxoguanine in the DNA duplex causes substantial alterations in the sugar-phosphate backbone conformation, inducing a BI→BII transition...
2016: PloS One
Saeed Izadi, Ramu Anandakrishnan, Alexey V Onufriev
Molecular Dynamics (MD) simulations based on the implicit solvent generalized Born (GB) models can provide significant computational advantages over the traditional explicit solvent simulations. However, the standard GB becomes prohibitively expensive for all-atom simulations of large structures; the model scales poorly, ~n^2, with the number of solute atoms. Here we combine our recently developed Optimal Point Charge Approximation (OPCA) with the Hierarchical Charge Partitioning (HCP) approximation to present an ~n log n multi-scale, yet fully atomistic, GB model (GB-HCPO)...
October 17, 2016: Journal of Chemical Theory and Computation
James Wilson, Leila Sloman, Zhiren He, Aleksei Aksimentiev
An inexpensive, reliable method for protein sequencing is essential to unraveling the biological mechanisms governing cellular behavior and disease. Current protein sequencing methods suffer from limitations associated with the size of proteins that can be sequenced, the time, and the cost of the sequencing procedures. Here, we report the results of all-atom molecular dynamics simulations that investigated the feasibility of using graphene nanopores for protein sequencing. We focus our study on the biologically significant phenylalanine-glycine repeat peptides (FG-nups)-parts of the nuclear pore transport machinery...
July 19, 2016: Advanced Functional Materials
Manabu Koike, Yasutomo Yutoku, Aki Koike
Understanding the molecular mechanisms of DNA double-strand break (DSB) repair processes, especially nonhomologous DNA-end joining (NHEJ), is critical for developing next-generation radiotherapies and chemotherapeutics for human and animal cancers. The localization, protein-protein interactions and post-translational modifications of core NHEJ factors, such as human Ku70 and Ku80, might play critical roles in controlling NHEJ activity. XRCC4-like factor (XLF) is a core NHEJ factor and plays a key role in the Ku-dependent NHEJ repair process in human cells...
October 14, 2016: Journal of Veterinary Medical Science
Martina I Gocke, Arnaud Huguet, Sylvie Derenne, Steffen Kolb, Michaela A Dippold, Guido L B Wiesenberg
Soils, paleosols and terrestrial sediments serve as archives for studying climate change, and represent important terrestrial carbon pools. Archive functioning relies on the chronological integrity of the respective units. Incorporation of younger organic matter (OM) e.g. by plant roots and associated microorganisms into deep subsoil and underlying soil parent material may reduce reliability of paleoenvironmental records and stability of buried OM. Long-term effects of sedimentary characteristics and deep rooting on deep subsoil microbial communities remain largely unknown...
October 13, 2016: Science of the Total Environment
Rosemeyre A Cordeiro, Daniela Santo, Dina Farinha, Arménio Serra, Henrique Faneca, Jorge F J Coelho
Cationic polymer-based vectors have been considered a promising strategy in gene therapy area due to their inherent ability to condense genetic material and successfully transfect cells. However, they usually exhibit high cytotoxicity. In this work, it is proposed the use of a tailor-made gene carrier based on a tri-block copolymer of poly[2-(dimethylamino)ethyl methacrylate] and poly(β-amino ester) (PDMAEMA-b-PβAE-b-PDMAEMA), the influence of the PβAE length being assessed. For this purpose, three different block copolymers were prepared varying the molecular weight of this segment...
October 12, 2016: Acta Biomaterialia
Jean-François Millau, Patrick Wijchers, Luc Gaudreau
A regulatory program involving hundreds of genes is coordinated by p53 to prevent carcinogenesis in response to stress. Given the importance of chromatin loops in gene regulation, we investigated whether DNA interactions participate in the p53 stress response. To shed light on this issue, we measured the binding dynamics of cohesin in response to stress. We reveal that cohesin is remodeled at specific loci during the stress response and that its binding within genes negatively correlates with transcription...
2016: PloS One
D C Rapaport
The question of how stiff polymers are able to pack into small containers is particularly relevant to the study of DNA packaging in viruses. A reduced version of the problem based on coarse-grained representations of the main components of the system-the DNA polymer and the spherical viral capsid-has been studied by molecular dynamics simulation. The results, involving longer polymers than in earlier work, show that as polymers become more rigid there is an increasing tendency to self-organize as spools that wrap from the inside out, rather than the inverse direction seen previously...
September 2016: Physical Review. E
Anca Macovei, Andrea Pagano, Paola Leonetti, Daniela Carbonera, Alma Balestrazzi, Susana S Araújo
The pre-germinative metabolism is among the most fascinating aspects of seed biology. The early seed germination phase, or pre-germination, is characterized by rapid water uptake (imbibition), which directs a series of dynamic biochemical events. Among those are enzyme activation, DNA damage and repair, and use of reserve storage compounds, such as lipids, carbohydrates and proteins. Industrial seedling production and intensive agricultural production systems require seed stocks with high rate of synchronized germination and low dormancy...
October 11, 2016: Plant Cell Reports
Salvador Damián-Zamacona, Paola Toledo-Ibelles, Mabel Z Ibarra-Abundis, Laura Uribe-Figueroa, Enrique Hernández-Lemus, Karla Paola Macedo-Alcibia, Blanca Delgado-Coello, Jaime Mas-Oliva, Juan Pablo Reyes-Grajeda
BACKGROUND: Although nowadays it is well known that the human transcriptome can importantly vary according to external or environmental condition, the reflection of this concept when studying oxidative stress and its direct relationship with gene expression profiling during the process of atherogenesis has not been thoroughly achieved. OBJECTIVE: The ability to analyze genome-wide gene expression through transcriptomics has shown that the genome responds dynamically to diverse stimuli...
2016: PloS One
Dana Krepel, David Gomez, Stefan Klumpp, Yaakov Levy
The key feature explaining the rapid recognition by a protein of its DNA target site lies in the combination of one- and three-dimensional (1D and 3D) diffusion, which allows efficient scanning of the many alternative sites. This facilitated diffusion mechanism is expected to be affected by cellular conditions, particularly crowding, given that up to 40% of the total cellular volume may by occupied by macromolecules. Using coarse-grained molecular dynamics and Monte-Carlo simulations, we show that the crowding particles can enhance facilitated diffusion and accelerate search kinetics...
October 10, 2016: Journal of Physical Chemistry. B
Nicola Festuccia, Agnès Dubois, Sandrine Vandormael-Pournin, Elena Gallego Tejeda, Adrien Mouren, Sylvain Bessonnard, Florian Mueller, Caroline Proux, Michel Cohen-Tannoudji, Pablo Navarro
Pluripotent mouse embryonic stem cells maintain their identity throughout virtually infinite cell divisions. This phenomenon, referred to as self-renewal, depends on a network of sequence-specific transcription factors (TFs) and requires daughter cells to accurately reproduce the gene expression pattern of the mother. However, dramatic chromosomal changes take place in mitosis, generally leading to the eviction of TFs from chromatin. Here, we report that Esrrb, a major pluripotency TF, remains bound to key regulatory regions during mitosis...
October 10, 2016: Nature Cell Biology
Zuzana Benková, Pavol Námer, Peter Cifra
The combined effects of the channel asymmetry and the closed chain topology on the chain extension, structure factor, and the orientation correlations were studied using coarse-grained molecular dynamics simulations for moderate chain lengths. These effects are related to applications in linearization experiments with a DNA molecule in nanofluidic devices. According to the aspect ratio, the channels are classified as a stripe or slabs. The chain segments do not have any freedom to move in the direction of the narrowest stripe size, being approximately the same size as the segment size...
October 12, 2016: Soft Matter
Zhiwen Li, Junfei Zhu, Junlin He
10-23 DNAzyme is a small catalytic DNA molecule. Studies on its conformation in solution are critical for understanding its catalytic mechanism and functional optimization. Based on our previous research, two fluorescent nucleoside analogues 1 and 2 were designed for the introduction of a pyrenyl group at one of the five dA residues in the catalytic core and the unpaired adenosine residue in its full-DNA substrate, respectively. Ten pyrenyl-pyrenyl pairs are formed in the DNAzyme-substrate complexes in solution for sensing the spacial positions of the five dA residues relative to the cleavage site using fluorescence spectra...
October 18, 2016: Organic & Biomolecular Chemistry
Feriel Melaine, Clothilde Coilhac, Yoann Roupioz, Arnaud Buhot
Small molecules (MW < 1000 Da) represent a large class of biomarkers of interest. Recently, a new class of biosensors has been emerging thanks to the recognition properties of aptamers, short DNA or RNA single strands, selected against such small molecular targets. Among them, an adenosine-specific aptamer has been largely described and used due to its remarkable affinity to this small target (KD = 6 μM). In this paper, we achieved the proof-of-principle of an aptasensor based on the thermodynamic follow-up of adenosine binding with engineered split-aptamer sequences...
September 29, 2016: Nanoscale
Matthias G Beuerle, Neil P Dufton, Anna M Randi, Ian R Gould
The ETS family of transcription factors regulate gene targets by binding to a core GGAA DNA-sequence. The ETS factor ERG is required for homeostasis and lineage-specific functions in endothelial cells, some subset of haemopoietic cells and chondrocytes; its ectopic expression is linked to oncogenesis in multiple tissues. To date details of the DNA-binding process of ERG including DNA-sequence recognition outside the core GGAA-sequence are largely unknown. We combined available structural and experimental data to perform molecular dynamics simulations to study the DNA-binding process of ERG...
October 3, 2016: Molecular BioSystems
Wenjuan Wang, Xiehuang Sheng, Shaolong Zhang, Fang Huang, Chuanzhi Sun, Jianbiao Liu, Dezhan Chen
The addition of the unnatural P:Z base pair to the four naturally occurring DNA bases expands the genetic alphabet and yields an artificially expanded genetic information system (AEGIS). Herein, the structural feature of oligonucleotides containing a novel unnatural P:Z base pair is characterized using both molecular dynamics and quantum chemistry. The results show that the incorporation of the novel artificial base pair (P:Z) preserves the global conformational feature of duplex DNA except for some local structures...
October 5, 2016: Physical Chemistry Chemical Physics: PCCP
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