The standard isothermal titration calorimetry (ITC) curve, characterized as a typical sigmoid is strictly confined by the so-called c value, which is a ratio of titrand concentration to K. The proper c value with a range from 5 to 500 is commonly recommended as a standard protocol in routine detection process for acquiring the reliable fitting results in 1:1 binding mode. However, if the c value is less than "1" due to the weak binding or low concentration of analyte, fitting precision gets unstable and susceptible to the data noise. Herein, we first got a deep discussion into the reliability of the fitting procedure for 1:1 binding mode by data simulation, then quantized the effect of several affecting factors on the precision of parameters estimation through mathematical analysis. Finally, we proposed the value of 2~4 times K for final ligand concentration is optimal for the ITC titration in low c system (c < 1). All the theoretical derivations were further verified by a practical experiment of Magnesium-EDTA binding test.
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http://dx.doi.org/10.1016/j.abb.2021.109045 | DOI Listing |
mSphere
January 2025
School of Medicine, Southern University of Science and Technology, Shenzhen, China.
The universal bacterial second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) plays critical roles in regulating a variety of bacterial functions such as biofilm formation and virulence. The metabolism of c-di-GMP is inversely controlled by diguanylate cyclases (DGCs) and phosphodiesterases (PDEs). Recently, increasing studies suggested that the protein-protein interactions between DGCs/PDEs and their partners appear to be a common way to achieve specific regulation.
View Article and Find Full Text PDFProtein Sci
February 2025
Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.
Loz1 is a zinc-responsive transcription factor in fission yeast that maintains cellular zinc homeostasis by repressing the expression of genes required for zinc uptake in high zinc conditions. Previous deletion analysis of Loz1 found a region containing two tandem CH zinc-fingers and an upstream "accessory domain" rich in histidine, lysine, and arginine residues to be sufficient for zinc-dependent DNA binding and gene repression. Here we report unexpected biophysical properties of this pair of seemingly classical CH zinc fingers.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Department of Chemistry and Pharmacy, Interdisciplinary Center for Molecular Materials, Friedrich-Alexander Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
pH-responsive polyamidoamine (PAMAM) dendrimers are used as well-defined building blocks to design light-switchable nano-assemblies in solution. The complex interplay between the photoresponsive di-anionic azo dye Acid Yellow 38 (AY38) and the cationic PAMAM dendrimers of different generations is presented in this study. Electrostatic self-assembly involving secondary dipole-dipole interactions provides well-defined assemblies within a broad size range (10 nm-1 μm) with various shapes.
View Article and Find Full Text PDFJ Sci Food Agric
January 2025
School of Food Science and Engineering, Hainan University, Haikou, People's Republic of China.
Background: This study aimed to elucidate the transport mechanism of lycopene-loaded nanomicelles to improve intestinal absorption of lycopene. The interactive mechanism between lycopene and nanomicelles was investigated through isothermal titration calorimetry (ITC). The cytotoxicity, cellular uptake, endocytosis, and intracellular transport pathways of lycopene-loaded nanomicelles were investigated using the Caco-2 cell model.
View Article and Find Full Text PDFBiosensors (Basel)
January 2025
School of Biomedical Sciences and Engineering, Koç University, 34450 Istanbul, Turkey.
Human monkeypox (Mpox) is a zoonotic disease caused by the Monkeypox virus (MPXV). As of 14 August 2024, the World Health Organization (WHO) has declared it a global health emergency. For Mpox, this was the second public health emergency of global significance in the past two years.
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