473 results match your criteria: "Heidelberg Institute for Theoretical Studies[Affiliation]"

Shocker─A Molecular Dynamics Protocol and Tool for Accelerating and Analyzing the Effects of Osmotic Shocks.

J Chem Theory Comput

January 2024

Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands.

The process of osmosis, a fundamental phenomenon in life, drives water through a semipermeable membrane in response to a solute concentration gradient across this membrane. In vitro, osmotic shocks are often used to drive shape changes in lipid vesicles, for instance, to study fission events in the context of artificial cells. While experimental techniques provide a macroscopic picture of large-scale membrane remodeling processes, molecular dynamics (MD) simulations are a powerful tool to study membrane deformations at the molecular level.

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The effective reproductive number Rt has taken a central role in the scientific, political, and public discussion during the COVID-19 pandemic, with numerous real-time estimates of this quantity routinely published. Disagreement between estimates can be substantial and may lead to confusion among decision-makers and the general public. In this work, we compare different estimates of the national-level effective reproductive number of COVID-19 in Germany in 2020 and 2021.

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Article Synopsis
  • Researchers identified broad-spectrum anti-infective agents from a library of 456 compounds through a high-throughput screening program, focusing on compounds effective against specific parasite species.
  • Using machine learning, they characterized and synthesized 44 compounds showing strong antiparasitic properties with minimal toxicity, highlighting one promising lead with a unique chemical structure.
  • The study utilized advanced chemoinformatic and machine learning tools to handle complex data, facilitating the selection and optimization of compounds for further biological and toxicological evaluation.
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Myristoyl's dual role in allosterically regulating and localizing Abl kinase.

Elife

October 2023

Heidelberg Institute for Theoretical Studies (HITS), Heidelberg University, Heidelberg, Germany.

c-Abl kinase, a key signaling hub in many biological processes ranging from cell development to proliferation, is tightly regulated by two inhibitory Src homology domains. An N-terminal myristoyl modification can bind to a hydrophobic pocket in the kinase C-lobe, which stabilizes the autoinhibitory assembly. Activation is triggered by myristoyl release.

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Dominantly inherited micro-satellite instable cancer - the four Lynch syndromes - an EHTG, PLSD position statement.

Hered Cancer Clin Pract

October 2023

Department of Tumor Biology, Institute of Cancer Research, Oslo University Hospital, PO Box 4950, 0424, NydalenOslo, Norway.

Article Synopsis
  • Dominantly inherited micro-satellite instable (MSI) cancers, linked to mutations in mismatch repair (MMR) genes (MSH2, MLH1, MSH6, PMS2), challenge traditional views of cancer development and are associated with unique syndromes known as Lynch syndromes.
  • Each Lynch syndrome has distinct risks and expressions, and it’s crucial to consider factors like specific gene mutation and sex when studying these cancers.
  • Advances in colonoscopy surveillance, aspirin usage, and immunotherapy represent significant progress in personalized medicine for managing and preventing inherited MSI cancers.
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Designing and optimizing graphene-based gas sensors entail constructing appropriate atomistic representations for the physisorption complex of an analyte on an infinite graphene sheet, then selecting accurate yet affordable methods for geometry optimizations and energy computations. In this work, diverse density functionals (DFs), coupled cluster theory, and symmetry-adapted perturbation theory (SAPT) in conjunction with a range of finite and periodic surface models of bare and supported graphene were tested for their ability to reproduce the experimental adsorption energies of CO on graphene in a low-coverage regime. Periodic results are accurately reproduced by the interaction energies extrapolated from finite clusters to infinity.

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Article Synopsis
  • Phylogenetic inference using maximum likelihood often explores vast search spaces, with different starting trees potentially leading to a single tree topology or multiple distinct topologies depending on input data.
  • Haag et al. developed a method to determine the difficulty of datasets for phylogenetic inference, showing that easier multiple sequence alignments (MSAs) tend to converge quickly to one topology, while more complex datasets present multiple optimal likelihood peaks.
  • The introduction of an adaptive tree search heuristic in RAxML-NG modifies search strategies based on predicted dataset difficulty, achieving significant speedups—averaging over 10× faster—particularly for easy and difficult datasets.
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The role of flow in the self-assembly of dragline spider silk proteins.

Biophys J

November 2023

Heidelberg Institute for Theoretical Studies, Heidelberg, Germany; Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany. Electronic address:

Hydrodynamic flow in the spider duct induces conformational changes in dragline spider silk proteins (spidroins) and drives their assembly, but the underlying physical mechanisms are still elusive. Here we address this challenging multiscale problem with a complementary strategy of atomistic and coarse-grained molecular dynamics simulations with uniform flow. The conformational changes at the molecular level were analyzed for single-tethered spider silk peptides.

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Natural variability in bee brain size and symmetry revealed by micro-CT imaging and deep learning.

PLoS Comput Biol

October 2023

Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, Toulouse, France.

Analysing large numbers of brain samples can reveal minor, but statistically and biologically relevant variations in brain morphology that provide critical insights into animal behaviour, ecology and evolution. So far, however, such analyses have required extensive manual effort, which considerably limits the scope for comparative research. Here we used micro-CT imaging and deep learning to perform automated analyses of 3D image data from 187 honey bee and bumblebee brains.

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Article Synopsis
  • * Research shows that by adjusting specific numerical thresholds in tools like RAxML-NG and IQ-TREE, tree inference times can be significantly improved without compromising the accuracy of the resulting trees.
  • * The study provides access to datasets and scripts used in the research, allowing others to replicate or build upon their findings via the provided links.
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The propensity of poorly water-soluble drugs to aggregate at supersaturation impedes their bioavailability. Supersaturated amorphous drug-salt-polymer systems provide an emergent approach to this problem. However, the effects of polymers on drug-drug interactions in aqueous phase are largely unexplored and it is unclear how to choose an optimal salt-polymer combination for a particular drug.

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Forecast evaluation is essential for the development of predictive epidemic models and can inform their use for public health decision-making. Common scores to evaluate epidemiological forecasts are the Continuous Ranked Probability Score (CRPS) and the Weighted Interval Score (WIS), which can be seen as measures of the absolute distance between the forecast distribution and the observation. However, applying these scores directly to predicted and observed incidence counts may not be the most appropriate due to the exponential nature of epidemic processes and the varying magnitudes of observed values across space and time.

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Real-time surveillance is a crucial element in the response to infectious disease outbreaks. However, the interpretation of incidence data is often hampered by delays occurring at various stages of data gathering and reporting. As a result, recent values are biased downward, which obscures current trends.

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The interplay between adsorption and aggregation of von Willebrand factor chains in shear flows.

Biophys J

October 2023

Max Planck Tandem Group in Computational Biophysics, Universidad de los Andes, Bogotá, Colombia; Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany. Electronic address:

Von Willebrand factor (VWF) is a giant extracellular glycoprotein that carries out a key adhesive function during primary hemostasis. Upon vascular injury and triggered by the shear of flowing blood, VWF establishes specific interactions with several molecular partners in order to anchor platelets to collagen on the exposed subendothelial surface. VWF also interacts with itself to form aggregates that, adsorbed on the surface, provide more anchor sites for the platelets.

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Molecular Dynamics Simulations of the Human Ecto-5'-Nucleotidase (h-ecto-5'-NT, CD73): Insights into Protein Flexibility and Binding Site Dynamics.

J Chem Inf Model

August 2023

Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, Brazil.

Human ecto-5'-nucleotidase (h-ecto-5'-NT, CD73) is a homodimeric Zn-binding metallophosphoesterase that hydrolyzes adenosine 5'-monophosphate (5'-AMP) to adenosine and phosphate. h-Ecto-5'-NT is a key enzyme in purinergic signaling pathways and has been recognized as a promising biological target for several diseases, including cancer and inflammatory, infectious, and autoimmune diseases. Despite its importance as a biological target, little is known about h-ecto-5'-NT dynamics, which poses a considerable challenge to the design of inhibitors of this target enzyme.

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RNA origami: design, simulation and application.

RNA Biol

January 2023

Biophysical Engineering Group, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg University, Heidelberg, Germany.

Design strategies for DNA and RNA nanostructures have developed along parallel lines for the past 30 years, from small structural motifs derived from biology to large 'origami' structures with thousands to tens of thousands of bases. With the recent publication of numerous RNA origami structures and improved design methods-even permitting co-transcriptional folding of kilobase-sized structures - the RNA nanotechnolgy field is at an inflection point. Here, we review the key achievements which inspired and enabled RNA origami design and draw comparisons with the development and applications of DNA origami structures.

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The talin-vinculin axis is a key mechanosensing component of cellular focal adhesions. How talin and vinculin respond to forces and regulate one another remains unclear. By combining single-molecule magnetic tweezers experiments, Molecular Dynamics simulations, actin-bundling assays, and adhesion assembly experiments in live cells, we here describe a two-ways allosteric network within vinculin as a regulator of the talin-vinculin interaction.

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Redox-active organic molecules, .., molecules that can relatively easily accept and/or donate electrons, are ubiquitous in biology, chemical synthesis, and electronic and spintronic devices, such as solar cells and rechargeable batteries, etc.

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Article Synopsis
  • - ALE and GeneRax are tools designed for analyzing how gene trees relate to species trees, using statistical models to understand events like gene duplication, transfer, and loss, while also helping to determine the origins of gene families and root species trees.
  • - Despite recent criticisms regarding their reliability in estimating gene duplication and transfer events, a study found that ALE and GeneRax perform well on both simulated data and real-world empirical data.
  • - Specifically, ALE demonstrates a consistent ability to capture variations in gene event frequencies according to known biological contexts, successfully rooting species trees in plants and opisthokonts, while providing comparable insights for Bacteria.
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Article Synopsis
  • The study explores two methods for assigning taxonomic classifications to operational taxonomic units (OTUs) from environmental sequencing data: VSEARCH (pairwise alignment) and EPA-ng (phylogenetic placement), highlighting differences in their results.
  • It finds that discrepancies between the two methods mainly occur when OTUs have low similarity to reference databases, suggesting potential challenges in accurate taxonomic classification at the subtaxon level.
  • The research emphasizes using GAPPA alongside EPA-ng for better evaluation of taxonomic assignments, particularly in cases with multiple placement options, and integrates evolutionary and ecological insights of the studied colpodean OTUs.
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Incongruence in the phylogenomics era.

Nat Rev Genet

December 2023

Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.

Genome-scale data and the development of novel statistical phylogenetic approaches have greatly aided the reconstruction of a broad sketch of the tree of life and resolved many of its branches. However, incongruence - the inference of conflicting evolutionary histories - remains pervasive in phylogenomic data, hampering our ability to reconstruct and interpret the tree of life. Biological factors, such as incomplete lineage sorting, horizontal gene transfer, hybridization, introgression, recombination and convergent molecular evolution, can lead to gene phylogenies that differ from the species tree.

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The chloroquine resistance transporter (PfCRT) confers resistance to a wide range of quinoline and quinoline-like antimalarial drugs in Plasmodium falciparum, with local drug histories driving its evolution and, hence, the drug transport specificities. For example, the change in prescription practice from chloroquine (CQ) to piperaquine (PPQ) in Southeast Asia has resulted in PfCRT variants that carry an additional mutation, leading to PPQ resistance and, concomitantly, to CQ re-sensitization. How this additional amino acid substitution guides such opposing changes in drug susceptibility is largely unclear.

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Chemical (molecular, quantum) machine learning relies on representing molecules in unique and informative ways. Here, we present the matrix of orthogonalized atomic orbital coefficients (MAOC) as a quantum-inspired molecular and atomic representation containing both structural (composition and geometry) and electronic (charge and spin multiplicity) information. MAOC is based on a cost-effective localization scheme that represents localized orbitals via a predefined set of atomic orbitals.

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Design, synthesis and biological evaluation of antiparasitic dinitroaniline-ether phospholipid hybrids.

Bioorg Chem

September 2023

National Hellenic Research Foundation, Institute of Chemical Biology, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece. Electronic address:

A series of nine novel ether phospholipid-dinitroaniline hybrids were synthesized in an effort to deliver more potent antiparasitic agents with improved safety profile compared to miltefosine. The compounds were evaluated for their in vitro antiparasitic activity against L. infantum, L.

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Article Synopsis
  • Researchers used methods from molecular evolution to calculate exact win probabilities for knockout tournaments instead of using slower simulations.
  • Their new open-source code is significantly faster, offering improvements two orders of magnitude faster than simulating and over two times faster than traditional methods.
  • They can now quickly assess prediction uncertainty by running extensive analyses, even for larger tournaments, on standard laptops in just minutes.
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