H-NS proteins act as osmotic sensors translating changes in osmolarity into altered DNA binding properties, thus, regulating enterobacterial genome organization and genes transcription. The molecular mechanism underlying the switching process and its conservation among H-NS family members remains elusive. Here, we focus on the H-NS family protein MvaT from Pseudomonas aeruginosa and demonstrate experimentally that its protomer exists in two different conformations, corresponding to two different functional states. In the half-opened state (dominant at low salt) the protein forms filaments along DNA, in the fully opened state (dominant at high salt) the protein bridges DNA. This switching is a direct effect of ionic strength on electrostatic interactions between the oppositely charged DNA binding and N-terminal domains of MvaT. The asymmetric charge distribution and intramolecular interactions are conserved among the H-NS family of proteins. Therefore, our study establishes a general paradigm for the molecular mechanistic basis of the osmosensitivity of H-NS proteins.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039000 | PMC |
http://dx.doi.org/10.1093/nar/gkz1226 | DOI Listing |
PLoS One
January 2025
Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, United States of America.
Severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1) and -2 (SARS-CoV-2) are beta-coronaviruses (β-CoVs) that have caused significant morbidity and mortality worldwide. Therefore, a better understanding of host responses to β-CoVs would provide insights into the pathogenesis of these viruses to identify potential targets for medical countermeasures. In this study, our objective is to use a systems biology approach to explore the magnitude and scope of innate immune responses triggered by SARS-CoV-1 and -2 infection over time in pathologically relevant human lung epithelial cells (Calu-3/2B4 cells).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2025
Center for Medical Research and Innovation, Shanghai Pudong Hospital, Institutes of Biomedical Sciences, Chinese Academy of Medical Sciences (RU069), Medical College of Fudan University, Shanghai 201399, China.
Ten-eleven translocation (TET) enzymes oxidize 5-methylcytosine (mC) in DNA, contributing to the regulation of gene transcription. Diverse mutations of TET2 are frequently found in various blood cancers, yet the full scope of their functional consequences has been unexplored. Here, we report that a subset of TET2 mutations identified in leukemia patients alter the substrate specificity of TET2 from acting on mC to thymine.
View Article and Find Full Text PDFACS Appl Bio Mater
January 2025
Department of Chemistry and Biochemistry, Thapar Institute of Engineering and Technology, Patiala-147001, India.
It has been well accumulated that G-quadruplex (G4-DNA) has great anticancer relevance, and various heterocyclic moieties have been synthesized and examined as potent G4-DNA binders with promising anticancer activity. Here, we have synthesized a series of naphthalimide-triazole-coumarin conjugates by substituting various amines and further examine their anticancer activity against 60 human cancer cell lines at 10 μM. One and five dose concentration results reveal low values of MG-MID GI for compounds including (3.
View Article and Find Full Text PDFExtremophiles
January 2025
Microbiology Laboratory, Department of Botany (DST-FIST and UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal, 731235, India.
To fish-out novel salt-tolerance genes, metagenomic DNA of moderately saline sediments of India's largest hypersaline Sambhar Lake was cloned in fosmid. Two functionally-picked clones helped the Escherichia coli host to tolerate 0.6 M NaCl.
View Article and Find Full Text PDFPhytopathology
January 2025
Michigan State University, Dept. Plant, Soil and Microbial Sciences, 105 CIPS, East Lansing, Michigan, United States, 48910;
Grape downy mildew, caused by poses a threat to grape cultivation globally. Early detection of fungicide resistance is critical for effective management. This study aimed to assess the prevalence and distribution of mutations associated with resistance to Quinone oxide inhibitors (QoI, FRAC 11), Quinone inside inhibitors (QiIs, FRAC 21, cyazofamid), Carboxylic acid amides (CAA, FRAC 41), and Quinone inside and outside inhibitor, stigmatellin binding mode (QioSI, FRAC 45, ametoctradin) in populations in the eastern United States and Canada; and evaluate whether these mutations are linked to fungicide resistance correlate with specific clades.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!