AI Article Synopsis
- Researchers aimed to find a mutation in the AraC protein of E. coli that allows DNA binding but prevents transcription activation.
- The mutation was identified by modifying a plasmid that produced a chimeric form of AraC and screening for proteins that hindered the normal function of wild-type AraC.
- The selected mutant had a specific change affecting its ability to bend DNA, bending it less than the wild-type, even though it still bound to the DNA.
Article Abstract
We sought a mutation in the DNA binding domain of the arabinose operon regulatory protein, AraC, of Escherichia coli that allows the protein to bind DNA normally but not activate transcription. The mutation was isolated by mutagenizing a plasmid overproducing a chimeric leucine zipper-AraC DNA binding domain and screening for proteins that were trans dominant negative with regard to wild-type AraC protein. The mutant with the lowest transcription activation of the araBAD promoter was studied further. It proved to alter a residue that had previously been demonstrated to contact DNA. Because the overproduced mutant protein still bound DNA in vivo, it is deficient in transcription activation for some reason other than absence of DNA binding. Using the phase-sensitive DNA bending assay, we found that wild-type AraC bends DNA about 90 degrees whereas the mutant bends DNA by a smaller amount.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC107421 | PMC |
| http://dx.doi.org/10.1128/JB.180.16.4227-4232.1998 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Characterizing temporal and global host innate immune responses against SARS-CoV-1 and -2 infection in pathologically relevant human lung epithelial cells.
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 PDFNeomorphic leukemia-derived mutations in the TET2 enzyme induce genome instability via a substrate shift from 5-methylcytosine to thymine.
Proc 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 PDFDeciphering Binding Potential of Naphthalimide-Coumarin Conjugate with c-MYC G-Quadruplex for Developing Anticancer Agents: A Spectroscopic and Molecular Modeling Approach.
ACS 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 PDFABC-type salt tolerance transporter genes are abundant and mutually shared among the microorganisms of the hypersaline Sambhar Lake.
Extremophiles
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 PDFPrevalence of Mutations Associated with QoI, QiI, QioSI and CAA Fungicide Resistance Within in North America and a Tool to Detect CAA Resistant Isolates.
Phytopathology
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 PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!