The M2 muscarinic receptor is the prototypic model of allostery in GPCRs, yet the molecular and the supramolecular determinants of such effects are unknown. Monomers and oligomers of the M2 muscarinic receptor therefore have been compared to identify those allosteric properties that are gained in oligomers. Allosteric interactions were monitored by means of a FRET-based sensor of conformation at the allosteric site and in pharmacological assays involving mutants engineered to preclude intramolecular effects. Electrostatic, steric, and conformational determinants of allostery at the atomic level were examined in molecular dynamics simulations. Allosteric effects in monomers were exclusively negative and derived primarily from intramolecular electrostatic repulsion between the allosteric and orthosteric ligands. Allosteric effects in oligomers could be positive or negative, depending upon the allosteric-orthosteric pair, and they arose from interactions within and between the constituent protomers. The complex behavior of oligomers is characteristic of muscarinic receptors in myocardial preparations.
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http://dx.doi.org/10.7554/eLife.11685 | DOI Listing |
Astrobiology
December 2024
Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Bari, Italy.
Agent-based simulations are set to describe the early biotic selection of oligomers made of monomers of different chirality. The simulations consider the spatial distribution of agents and resources, the balance of biomass of different chirality, and the balance of chemical energy. Following the well-known Wald's hypothesis, a disadvantage is attributed to the change in chirality along the biochemical sequence.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
LAQV@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
Polyethylene terephthalate (PET) has been widely used in plastic products, leading to massive PET waste accumulation in ecosystems worldwide. Efforts to find greener processes for dealing with post-consumer PET waste led to the discovery of PET-degrading enzymes such as PETase (PETase). studies have provided valuable contributions to this field, shedding light on the catalytic mechanisms and substrate interactions in many PET hydrolase enzymes.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Physical Science and Technology, Ningbo University, Ningbo 315211, China; Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States. Electronic address:
Human calcitonin (hCT) is a peptide hormone that regulates calcium homeostasis, but its abnormal aggregation can disrupt physiological functions and increase the risk of medullary thyroid carcinoma. To elucidate the mechanisms underlying hCT aggregation, we investigated the self-assembly dynamics of hCT segments (hCT, hCT, and hCT) and the folding and dimerization of full-length hCT through microsecond atomistic discrete molecular dynamics (DMD) simulations. Our results revealed that hCT and hCT predominantly existed as isolated monomers with transient small-sized oligomers, indicating weak aggregation tendencies.
View Article and Find Full Text PDFJ Pharm Anal
November 2024
National Key Laboratory of Chinese Medicine Modernization, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China.
In this study, 34 deep eutectic solvents (DESs) were successfully prepared for the extraction of proanthocyanidin from Rhodiolae Crenulatae Radix et Rhizomes. The extraction process was optimized using single factor exploration and Box-Behnken design-response surface analysis. The extraction rate was significantly improved when the molar ratio of choline chloride to 1,3-propanediol was 1:3.
View Article and Find Full Text PDFLinear aliphatic oligoesters derived from ε-caprolactone (CL) were synthesized by ring-opening polymerization (ROP) using terpene alcohols that have antibacterial activity as initiators (nerol, geraniol, β-citronellol and farnesol). Ammonium decamolybdate (NH)[MoO] was used as a catalyst. From previous oligoesters, monodisperse species of monomers, dimers, and trimers were isolated by flash column chromatography (FCC).
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