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DNA molecular dynamics

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https://www.readbyqxmd.com/read/28822069/characterization-of-ofloxacin-interaction-with-mutated-a91v-quinolone-resistance-determining-region-of-dna-gyrase-in-mycobacterium-leprae-through-computational-simulation
#1
J Nisha, V Shanthi
Mycobacterium leprae, the causal agent of leprosy is non-cultivable in vitro. Thus, the assessment of antibiotic activity against Mycobacterium leprae depends primarily upon the time-consuming mouse footpad system. The GyrA protein of Mycobacterium leprae is the target of the antimycobacterial drug, Ofloxacin. In recent times, the GyrA mutation (A91V) has been found to be resistant to Ofloxacin. This phenomenon has necessitated the development of new, long-acting antimycobacterial compounds. The underlying mechanism of drug resistance is not completely known...
August 18, 2017: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28815856/molecular-dynamics-insights-into-polyamine-dna-binding-modes-implications-for-cross-link-selectivity
#2
Emmanuelle Bignon, Chen-Hui Chan, Christophe Morell, Antonio Monari, Jean-Luc Ravanat, Elise Dumont
Biogenic polyamines, which play a role in DNA condensation and stabilization, are ubiquitous and are found at millimolar concentration in the nucleus of eukaryotic cells. The interaction modes of three polyamines-putrescine (Put), spermine (Spm), and spermidine (Spd)-with a self-complementary 16 base pair (bp) duplex, are investigated by all-atom explicit-solvent molecular dynamics. The length of the amine aliphatic chain leads to a change of the interaction mode from minor groove binding to major groove binding...
August 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28814526/hiv-1-exploits-dynamic-multi-aminoacyl-trna-synthetase-complex-to-enhance-viral-replication
#3
Alice A Duchon, Corine St-Gelais, Nathan Titkemeier, Joshua Hatterschide, Li Wu, Karin Musier-Forsyth
A hallmark of retroviruses such as human immunodeficiency virus type 1 (HIV-1) is reverse transcription of genomic RNA to DNA, a process that is primed by cellular tRNAs. HIV-1 recruits human tRNA(Lys3) to serve as the reverse transcription primer via an interaction between lysyl-tRNA synthetase (LysRS) and the HIV-1 Gag polyprotein. LysRS is normally sequestered in a multi-aminoacyl-tRNA synthetase complex (MSC). Previous studies demonstrated that components of the MSC can be mobilized in response to certain cellular stimuli, but how LysRS is redirected from the MSC to viral particles for packaging is unknown...
August 16, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28814516/baculovirus-molecular-evolution-via-gene-turnover-and-recurrent-positive-selection-of-key-genes
#4
Tom Hill, Robert L Unckless
Hosts and viruses are locked in an evolutionary arms race. Hosts are constantly evolving to suppress virulence and replication, while viruses, reliant on host machinery for survival and reproduction, develop counter-strategies to escape this immune defense. Viruses must also adapt to novel conditions when establishing themselves in a host species. Both processes provide strong selection for viral adaptation. Understanding adaptive evolution in insect viruses can help us better understand adaptive evolution in general, and is important due to their use as biocontrol agents, and for protecting ecologically or economically important species from outbreaks...
August 16, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28814266/lack-of-satellite-dna-species-specific-homogenization-and-relationship-to-chromosomal-rearrangements-in-monitor-lizards-varanidae-squamata
#5
Ornjira Prakhongcheep, Watcharaporn Thapana, Aorarat Suntronpong, Worapong Singchat, Khampee Pattanatanang, Rattanin Phatcharakullawarawat, Narongrit Muangmai, Surin Peyachoknagul, Kazumi Matsubara, Tariq Ezaz, Kornsorn Srikulnath
BACKGROUND: Satellite DNAs (stDNAs) are highly repeated sequences that constitute large portions of any genome. The evolutionary dynamics of stDNA (e.g. copy number, nucleotide sequence, location) can, therefore, provide an insight into genome organization and evolution. We investigated the evolutionary origin of VSAREP stDNA in 17 monitor lizards (seven Asian, five Australian, and five African) at molecular and cytogenetic level. RESULTS: Results revealed that VSAREP is conserved in the genome of Asian and Australian varanids, but not in African varanids, suggesting that these sequences are either differentiated or lost in the African varanids...
August 16, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28813625/detection-of-first-line-drug-resistance-mutations-and-drug-protein-interaction-dynamics-from-tuberculosis-patients-in-south-india
#6
Somanna Ajjamada Nachappa, Sumana M Neelambike, Chokkanna Amruthavalli, Nallur B Ramachandra
Diagnosis of drug-resistant tuberculosis predominantly relies on culture-based drug susceptibility testing, which take weeks to produce a result and a more time-efficient alternative method is multiplex allele-specific PCR (MAS-PCR). Also, understanding the role of mutations in causing resistance helps better drug designing. AIMS: To evaluate the ability of MAS-PCR in the detection of drug resistance and to understand the mechanism of interaction of drugs with mutant proteins in Mycobacterium tuberculosis...
August 16, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28813011/insights-into-the-effect-of-the-g245s-single-point-mutation-on-the-structure-of-p53-and-the-binding-of-the-protein-to-dna
#7
Marco Gaetano Lepre, Sara Ibrahim Omar, Gianvito Grasso, Umberto Morbiducci, Marco Agostino Deriu, Jack A Tuszynski
The transcription factor p53 is a potent tumor suppressor dubbed as the "guardian of the genome" because of its ability to orchestrate protective biological outputs in response to a variety of oncogenic stresses. Mutation and thus inactivation of p53 can be found in 50% of human tumors. The majority are missense mutations located in the DNA binding region. Among them, G245S is known to be a structural hotspot mutation. To understand the behaviors and differences between the wild-type and mutant, both a dimer of the wild type p53 (wt-p53) and its G245S mutant (G245S-mp53), complexed with DNA, were simulated using molecular dynamics for more than 1 μs...
August 16, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28811103/identification-and-phylogenetic-position-of-naegleria-spp-from-geothermal-springs-in-italy
#8
M Montalbano Di Filippo, A Novelletto, D Di Cave, F Berrilli
Naegleria spp. are free-living amoebae belonging to the family Vahlkampfiidae, in the class Heterolobosea. Among the recognized species, Naegleria fowleri causes primary amoebic meningoencephalitis (PAM), while two other species, Naegleria australiensis and Naegleria italica, have been reported as pathogenic in experimental animals. Due to the thermotolerance properties of some species, geothermal water sources including hot springs represent suitable habitats for their proliferation. The main aim of this study was a year-round sampling in two geothermal springs in Central Italy, to investigate the presence of Naegleria spp...
August 12, 2017: Experimental Parasitology
https://www.readbyqxmd.com/read/28810800/confinement-curvature-and-attractive-interaction-effects-on-polymer-surface-adsorption
#9
Wei Chien, Yeng-Long Chen
We investigate the conformation and dynamics of a semi-flexible polymer near an attractive plane or a cylindrical post using Langevin dynamics. We characterize the transition from the desorbed to absorbed state and quantify how absorption depends on the attraction interaction, polymer molecular weight, polymer flexibility, intra-polymer interaction, and micro-confinement. We find that the critical point of adsorption for ideal flexible polymers only weakly depends on confinement. However, the critical point of adsorption increases significantly for self-avoiding flexible polymers and under confinement, deviating from scaling theory predictions...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28810797/asymmetric-breathing-motions-of-nucleosomal-dna-and-the-role-of-histone-tails
#10
Kaushik Chakraborty, Sharon M Loverde
The most important packing unit of DNA in the eukaryotic cell is the nucleosome. It undergoes large-scale structural re-arrangements during different cell cycles. For example, the disassembly of the nucleosome is one of the key steps for DNA replication, whereas reassembly occurs after replication. Thus, conformational dynamics of the nucleosome is crucial for different DNA metabolic processes. We perform three different sets of atomistic molecular dynamics simulations of the nucleosome core particle at varying degrees of salt conditions for a total of 0...
August 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28810119/conformational-flexibility-of-the-benzyl-guanine-adduct-in-a-bypass-polymerase-active-site-permits-replication-insights-from-molecular-dynamics-simulations
#11
Katie A Wilson, Stacey D Wetmore
Although translesion synthesis (TLS) polymerases play key roles in replicating DNA that contains nucleobase addition products (adducts), there are many unknowns about their function. The present work gains indispensable structural insights from molecular dynamics simulations on the replication of O6-benzyl-guanine (Bz-dG) prior to bond formation during dCTP insertion opposite the adduct by Dpo4. When combined with previous X-ray crystal structures of the Bz-dG extension complex, molecular details are now available for each stage during a single TLS replication cycle for this carcinogenic lesion...
August 15, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/28809101/a-microsphere-supported-lipid-bilayer-platform-for-dna-reactions-on-a-fluid-surface
#12
Aurora Fabry-Wood, Madalyn Elise Fetrow, Carl W Brown Iii, Nicholas A Baker, Nadiezda Fernandez Oropeza, Andrew P Shreve, Gabriel A Montano, Darko Stefanovic, Matthew R Lakin, Steven W Graves
We report a versatile microsphere-supported lipid bilayer system that can serve as a general-purpose platform for implementing DNA nanotechnologies on a fluid surface. To demonstrate our platform, we implemented both toehold-mediated strand displacement (TMSD) and DNAzyme reactions, which are typically performed in solution and which are the cornerstone of DNA-based molecular logic and dynamic DNA nanotechnology, on the surface. We functionalized microspheres bearing supported lipid bilayers (µSLBs) with membrane-bound nucleic acid components...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28805211/all-atom-md-indicates-ion-dependent-behavior-of-therapeutic-dna-polymer
#13
Ryan L Melvin, William H Gmeiner, Freddie R Salsbury
Understanding the efficacy of and creating delivery mechanisms for therapeutic nucleic acids requires understanding structural and kinetic properties which allow these polymers to promote the death of cancerous cells. One molecule of interest is a 10 mer of FdUMP (5-fluoro-2'-deoxyuridine-5'-O-monophosphate) - also called F10. Here we investigate the structural and kinetic behavior of F10 in intracellular and extracellular solvent conditions along with non-biological conditions that may be efficacious in in vitro preparations of F10 delivery systems...
August 14, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28802828/photolyase-dynamics-and-electron-transfer-mechanisms-of-dna-repair
#14
REVIEW
Meng Zhang, Lijuan Wang, Dongping Zhong
Photolyase, a flavoenzyme containing flavin adenine dinucleotide (FAD) molecule as a catalytic cofactor, repairs UV-induced DNA damage of cyclobutane pyrimidine dimer (CPD) and pyrimidine-pyrimidone (6-4) photoproduct using blue light. The FAD cofactor, conserved in the whole protein superfamily of photolyase/cryptochromes, adopts a unique folded configuration at the active site that plays a critical functional role in DNA repair. Here, we review our comprehensive characterization of the dynamics of flavin cofactor and its repair photocycles by different classes of photolyases on the most fundamental level...
August 9, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28801915/manganese-and-1-methyl-4-phenylpyridinium-mpp-induced-neurotoxicity-indicate-differences-in-morphological-electrophysiological-and-genome-wide-alterations-implications-for-idiopathic-parkinson-s-disease
#15
Rajeswara Babu Mythri, Narayana Reddy Raghunath, Santosh Chandrakant Narwade, Mirazkar DasharathaRao Pandareesh, Kollarkandi Rajesh Sabitha, Mohamad Aiyaz, Bipin Chand, Manas Sule, Krittika Ghosh, Senthil Kumar, Bhagyalakshmi Shankarappa, Soundarya Soundararajan, Phalguni Anand Alladi, Meera Purushottam, Narayanappa Gayathri, Deepti Dileep Deobagkar, Thenkanidiyoor Rao Laxmi, Srinivas Bharath Muchukunte Mukunda
Idiopathic Parkinson's disease (iPD) and manganese-induced atypical Parkinsonism are characterized by movement disorder and nigrostriatal pathology. Although clinical features, brain region involved and responsiveness to levodopa distinguish both, differences at the neuronal level are largely unknown. We studied the morphological, neurophysiological and molecular differences in dopaminergic neurons exposed to the PD toxin 1-methyl-4-phenylpyridinium ion (MPP(+) ) and manganese (Mn) followed by validation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and Mn mouse models...
August 12, 2017: Journal of Neurochemistry
https://www.readbyqxmd.com/read/28799760/biomolecular-structure-information-from-high-speed-quantum-mechanical-electronic-spectra-calculation
#16
Jakob Seibert, Christoph Bannwarth, Stefan Grimme
A fully quantum mechanical (QM) treatment to calculate electronic absorption (UV-Vis) and circular dichroism (CD) spectra of typical biomolecules with thousands of atoms is presented. With our highly efficient sTDA-xTB method, spectra averaged along structures from molecular dynamics (MD) simulations can be computed in a reasonable time frame on standard desktop computers. This way, non-equilibrium structure and conformational as well as purely quantum mechanical effects like charge-transfer or exciton-coupling are included...
August 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28799119/modeling-dmpc-lipid-membranes-with-sirah-force-field
#17
Exequiel E Barrera, Ezequiel N Frigini, Rodolfo D Porasso, Sergio Pantano
Coarse-grained simulation schemes are increasingly gaining popularity in the scientific community because of the significant speed up granted, allowing a considerable expansion of the accessible time and size scales accessible to molecular simulations. However, the number of compatible force fields capable of representing ensembles containing different molecular species (i.e., Protein, DNA, etc) is still limited. Here, we present a set of parameters and simplified representation for lipids compatible with the SIRAH force field for coarse-grained simulations ( http://www...
August 10, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28798968/stretching-of-surface-tethered-polymers-in-pressure-driven-flow-under-confinement
#18
Tamal Roy, Kai Szuttor, Jens Smiatek, Christian Holm, Steffen Hardt
We study the effect of pressure-driven flow on a single surface-tethered DNA molecule confined between parallel surfaces. The influence of flow and channel parameters as well as the length of the molecules on their extension and orientation is explored. In the experiments the chain conformations are imaged by laser scanning confocal microscopy. We find that the fractional extension of the tethered DNA molecules mainly depends on the wall shear stress, with effects of confinement being very weak. Experiments performed with molecules of different contour length show that the fractional extension is a universal function of the product of the wall shear stress and the contour length, a result that can be obtained from a simple scaling relation...
August 11, 2017: Soft Matter
https://www.readbyqxmd.com/read/28796515/optimal-length-of-conformational-transition-region-in-protein-search-for-targets-on-dna
#19
Maria P Kochugaeva, Alexander M Berezhkovskii, Anatoly B Kolomeisky
The starting point of many fundamental biological processes is associated with protein molecules finding and recognizing specific sites on DNA. However, despite a large number of experimental and theoretical studies on protein search for targets on DNA, many molecular aspects of underlying mechanisms are still not well understood. Experiments show that proteins bound to DNA can switch between slow recognition and fast search conformations. However, from a theoretical point of view, such conformational transitions should slow down the protein search for specific sites on DNA, in contrast to available experimental observations...
August 10, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28794984/seasonality-richness-and-prevalence-of-intestinal-parasites-of-three-neotropical-primates-alouatta-seniculus-ateles-hybridus-and-cebus-versicolor-in-a-fragmented-forest-in-colombia
#20
Silvia Rondón, Mario Ortiz, Cielo León, Nelson Galvis, Andrés Link, Camila González
Studies on parasites infecting non-human primates are essential to better understand the potential threat to humans of zoonoses transmission, particularly under the current processes of pervasive land use change and biodiversity loss. The natural ecosystems in the Middle Magdalena river basin in Colombia have suffered a dramatic reduction and transformation into pastures and agroindustrial monocultures, threatening their biodiversity, and probably affecting the dynamics between parasites and their hosts, as well as altering the disease transmission cycles between wild populations and humans...
December 2017: International Journal for Parasitology. Parasites and Wildlife
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