Long-lived states (LLS) are relaxation-favored spin population distributions of J-coupled magnetic nuclei. LLS were measured, along with classical (1)H and (15)N relaxation rate constants, in amino acids of the N-terminal Unique domain of the c-Src kinase, which is disordered in vitro under physiological conditions. The relaxation rates of LLS can probe motions and interactions in biomolecules. LLS of the aliphatic protons of glycines, with lifetimes approximately four times longer than their spin-lattice relaxation times, are reported for the first time in an intrinsically disordered protein domain. LLS relaxation experiments were integrated with 2D spectroscopy methods, further adapting them for studies on proteins.
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http://dx.doi.org/10.1002/mrc.4008 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada.
The ability to manipulate excited-state decay cascades using molecular structure is essential to the application of abundant-metal photosensitizers and chromophores. Ligand design has yielded some spectacular results elongating charge-transfer excited state lifetimes of Fe(II) coordination complexes, but triplet metal-centered (MC) excited states─recently demonstrated to be critical to the photoactivity of isoelectronic Co(III) polypyridyls─have to date remained elusive, with temporally isolable examples limited to the picosecond regime. With this report, we show how strong-field donors and intramolecular π-stacking can conspire to stabilize a long-lived MC excited state for a remarkable 4.
View Article and Find Full Text PDFACS Nano
January 2025
Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore.
Transmembrane signaling receptors, such as integrins, organize as nanoclusters that provide several advantages, including increasing avidity, sensitivity (increasing the signal-to-noise ratio), and robustness (signaling threshold) of the signal in contrast to signaling by single receptors. Furthermore, compared to large micron-sized clusters, nanoclusters offer the advantage of rapid turnover for the disassembly of the signal. However, whether nanoclusters function as signaling hubs remains poorly understood.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, The University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States.
ConspectusLight-driven polymerizations and their application in 3D printing have revolutionized manufacturing across diverse sectors, from healthcare to fine arts. Despite the popularized notion that with 3D printing "imagination is the only limit", we and others in the scientific community have identified fundamental hurdles that restrict our capabilities in this space. Herein, we describe the group's efforts in developing photochemical systems that respond to nontraditional colors of light to elicit the rapid, spatiotemporally controlled formation of plastics.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials and Micro-Nano Devices, Renmin University of China, Beijing 100872, China.
Photosynthesis in nature begins with light harvesting. The special pigment-protein complex converts sunlight into electron excitation that is transmitted to the reaction center, which triggers charge separation. Evidence shows that quantum coherence between electron excited states is important in the excitation energy transfer process.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2025
Department of Chemistry, College of Science and Engineering, Western Washington University, 516 High Street, Bellingham, WA, 98229, USA.
Fluorescent lifetimes of dissolved organic matter (DOM) and associated physicochemical parameters were measured over 14 months in an estuary in Southern California, USA. Measurements were made on 77 samples from sites near the inlet, mid-estuary, and outlet to maximize the range of physicochemical variables. Time-resolved fluorescence data were well fit to a triexponential model with an intermediate lifetime component (τ: 1 to 5 ns), a long lifetime component (τ: 2 to 15 ns), and a short lifetime component (τ: < 1 ns).
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