One of the main structural features of the mature HIV-1 virion is the matrix protein (p17). This partially globular protein presents four helixes centrally organized and a fifth one, H5, projecting away from the packed bundle of helixes. Comparison between solution and crystallographic data of p17 indicates a 6 A displacement of a short 3(10) helix and a partial unfolding of H5 in solution related to crystal. While the behavior of the 3(10) helix has been previously addressed to virion assembly, the relevance and origin of H5 partial unfolding is possibly related to the contacts between p17 and other viral elements, such as p24. In this context, we present a 40 ns conformational sampling of monomeric p17 using molecular dynamics simulations. The performed simulations presented a progressive conversion of the p17 crystallographic structure to the NMR conformation, suggesting that the biological form of this protein may have its C-terminal portion partially unfolded.
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http://dx.doi.org/10.1016/j.jmgm.2006.09.009 | DOI Listing |
Chemphyschem
January 2025
Fachbereich Chemie, Philipps-Universität Marburg, 35032, Marburg, Germany.
Both, molecular chemical reactions and transport of atoms in solid media are determined by the energy landscape in which the seemingly different processes take place. Chemical reactions can be described as cooperative translocation of two chemical entities on a common potential energy surface. Transport of atoms in a solid can be envisaged as the translocation of a single particle in the potential energy landscape of all other particles constituting the solid.
View Article and Find Full Text PDFBMC Cancer
January 2025
Jiangxi Provincial Key Laboratory of Child Development and Genetics, Jiangxi Provincial Children's Hospital, No. 122 of YangMing Road, DongHu District, NanChang, 330006, China.
Background: Hepatocellular carcinoma (HCC) is a prevalent primary liver malignancy and a leading cause of cancer-related mortality worldwide. Despite advancements in therapeutic strategies, the 5-year survival rate for individuals undergoing curative resection remains between 10% and 15%. Consequently, identifying molecular targets that specifically inhibit the proliferation and metastasis of HCC cells is critical for improving treatment outcomes.
View Article and Find Full Text PDFNat Struct Mol Biol
January 2025
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
Transcription activators are said to stimulate gene expression by 'recruiting' coactivators, yet this vague term fits multiple kinetic models. To directly analyze the dynamics of activator-coactivator interactions, single-molecule microscopy was used to image promoter DNA, a transcription activator and the Spt-Ada-Gcn5 acetyltransferase (SAGA) complex within yeast nuclear extract. SAGA readily but transiently binds nucleosome-free DNA without an activator, while chromatin association occurs primarily when an activator is present.
View Article and Find Full Text PDFNat Chem Biol
January 2025
Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Medical Epigenetics, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
Chromatin and transcription regulators are critical to defining cell identity through shaping epigenetic and transcriptional landscapes, with their misregulation being closely linked to oncogenesis. Pharmacologically targeting these regulators, particularly the transcription-activating BET proteins, has emerged as a promising approach in cancer therapy, yet intrinsic or acquired resistance frequently occurs, with poorly understood mechanisms. Here, using genome-wide CRISPR screens, we find that BET inhibitor efficacy in mediating transcriptional silencing and growth inhibition depends on the auxiliary/arm/tail module of the Integrator-PP2A complex (INTAC), a global regulator of RNA polymerase II pause-release dynamics.
View Article and Find Full Text PDFMol Psychiatry
January 2025
Siena Brain Investigation and Neuromodulation Lab, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
Ketamine, a dissociative compound, shows promise in treating mood disorders, including treatment-resistant depression (TRD) and bipolar disorder (BD). Despite its therapeutic potential, the neurophysiological mechanisms underlying ketamine's effects are not fully understood. This study explored acute neurophysiological changes induced by subanesthetic doses of ketamine in BD patients with depression using electroencephalography (EEG) biomarkers.
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