The side group of the amino acid arginine is typically in its guanidinium protonated form under physiological conditions and participates in a broad range of ligand binding and charge transfer processes of proteins. The recognition of phosphate moieties by guanidinium plays a particularly key role in the interactions of proteins with ATP and nucleic acids. Moreover, it has been recently identified as the driving force for the inhibition of kinase phosphorilation activity by guanidinium derivatives devised as potential anticancer agents. We report on a fundamental investigation of the interactions and coordination arrangements formed by guanidinium with phosphoric, phosphate, and pyrophosphate groups. Action vibrational spectroscopy and quantum chemical computations are employed to characterize the conformations of benchmark positively charged complexes isolated in an ion trap. The multidentate structure of guanidinium and of the phosphate groups gives rise to a rich conformational landscape with a particular relevance of tweezer-like configurations, where phosphate is effectively trapped by two guanidinium cations. The pyrophosphate complex incorporates a Na cation, which serves to compare the interactions associated with the localized versus diffuse charge distributions of the alkali cation and guanidinium, respectively, within a common supramolecular framework.
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http://dx.doi.org/10.1021/acs.jpcb.9b06201 | DOI Listing |
Anal Methods
January 2025
School of Pharmacy, Wannan Medical College, Wuhu 241002, China.
A label-free photoelectrochemical (PEC) sensor for detecting theophylline (TP) was exploited based on electrodes modified with a nanocomposite of polydopamine nanospheres (PDSs) and gold nanoparticles (AuNPs). PDS particles were prepared by oxidative autopolymerization, and their reducibility was utilized in one step to reduce the gold nanoparticles . The AuNPs-PDS/ZnS PEC sensor was constructed by electrochemical deposition and drop coating.
View Article and Find Full Text PDFAnal Bioanal Chem
January 2025
Gene Engineering and Biotechnology of Beijing Key Laboratory, College of Life Sciences, Beijing Normal University, Beijing, 100875, China.
Alkaline phosphatase (ALP) is a nonspecific phosphatase, and its interaction with substrates mainly depends on the recognition of phosphate groups on the substrate. Previous enzymatic research has focused mainly on the enzymatic reaction kinetics of the inorganic small molecule p-nitrophenol phosphate (pNPP) as a substrate, but its interaction with biomacromolecule substrates has not been reported. In current scientific research, ALP is often used for molecular cloning, such as removing the 5' termini of nucleic acids.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Physics, Novosibirsk State University, 2 Pirogov Str., Novosibirsk 630090, Russia.
Nowadays, nucleic acid derivatives capable of modulating gene expression at the RNA level have gained widespread recognition as promising therapeutic agents. A suitable degree of biological stability of oligonucleotide therapeutics is required for in vivo application; this can be most expeditiously achieved by the chemical modification of the internucleotidic phosphate group, which may also affect their cellular uptake, tissue distribution and pharmacokinetics. Our group has previously developed a strategy for the chemical modification of the phosphate group via the Staudinger reaction on a solid phase of the intermediate dinucleoside phosphite triester and a range of, preferably, electron deficient organic azides such as sulfonyl azides during automated solid-phase DNA synthesis according to the conventional β-cyanoethyl phosphoramidite scheme.
View Article and Find Full Text PDFFEBS Lett
January 2025
Department of Biomedical Sciences, Creighton University, Omaha, NE, USA.
Protein-protein interactions involving 14-3-3 proteins regulate various cellular activities in normal and pathological conditions. These interactions have mostly been reported to be phosphorylation-dependent, but the 14-3-3 proteins also interact with unphosphorylated proteins. In this work, we investigated whether phosphorylation is required, or, alternatively, whether negative charges are sufficient for 14-3-3ε binding.
View Article and Find Full Text PDFBMB Rep
January 2025
Division of Endocrinology and Metabolism, Department of Internal Medicine, Korea University College of Medicine, Seoul 02841, Korea.
G protein-coupled receptor 40 (GPR40) is gaining recognition as a potential therapeutic target for several metabolic disturbances, such as hyperglycemia and excessive inflammation. GPR40 is expressed in various tissues, including the heart; however, its specific roles in cardiomyocytes remain unknown. The objective of the present study was to investigate whether treatment with AM1638, a GPR40-full agonist, reduces palmitate-mediated cell damage in H9c2 rat cardiomyocytes.
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