Red fluorescent proteins (RFPs) are widely used probes for monitoring subcellular processes with extremely high spatial and temporal precision. In this work, we employed spectrally resolved transient absorption (SRTA) and two-dimensional double quantum coherence (2D2Q) spectroscopy to investigate the excited state electronic structure of mPlum, a well-known RFP. The SRTA spectra reveal the presence of excited state absorption features at both the low- and high-energy sides of the dominant ground state bleach contribution. The 2D2Q spectra measured at several excitation wavelengths reveal a peak pattern consistent with the presence of more than three electronic states (i.e., ground, excited, and doubly excited). Numerical modeling of this response suggests that the features are consistent with a 1-1-2 electronic structure. The two closely spaced (∼1500 cm(-1)) levels in the double quantum manifold appear at opposite anharmonicities relative to twice the energy of the lowest energy transition. These observations explain the excited state absorption contributions observed in spectrally resolved transient grating and transient absorption measurements and demonstrate the utility of multidimensional spectroscopy in unraveling congested spectra relative to conventional one-dimensional methods.
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http://dx.doi.org/10.1021/jp5119772 | DOI Listing |
Arch Microbiol
January 2025
Department of Botany, CMS College Kottayam, Kottayam, Kerala, 686001, India.
Among all photosynthetic life forms, cyanobacteria exclusively possess a water-soluble, light-sensitive carotenoprotein complex known as orange carotenoid proteins (OCPs), crucial for their photoprotective mechanisms. These protein complexes exhibit both structural and functional modularity, with distinct C-terminal (CTD) and N-terminal domains (NTD) serving as light-responsive sensor and effector regions, respectively. The majority of cyanobacterial genomes contain genes for OCP homologs and related proteins, highlighting their essential role in survival of the organism over time.
View Article and Find Full Text PDFJ Fluoresc
January 2025
Department of Physics, R. T. M. Nagpur University, 440033, Nagpur, India.
The preparation of new phosphor with outstanding luminescent properties for white light-emitting diodes (WLEDs) is consistently a challenging. Here in the present study, A novel white-emitting chloropatite phosphor Ca(PO)Cl:Eu was synthesized via the pechini sol gel synthesis with citric acid and polyethylene glycol (PEG) acid as a fuel at 850 °C systematically investigating the impact of doping concentration and synthesis temperature on both photoluminescence properties and crystal phase. The structural characteristics and crystalline nature of the prepared sample were investigated by using X-ray diffraction (XRD) patterns and Fourier transform infrared (FT-IR) spectra.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, P. R. China.
Photoluminescence is one of the most intriguing properties of metal nanoclusters derived from their molecular-like electronic structure, however, achieving high photoluminescence quantum yield (PLQY) of metal core-dictated fluorescence remains a formidable challenge. Here, we report efficient suppression of the total structural vibrations and rotations, and management of the pathways and rates of the electron transfer dynamics to boost a near-unity absolute PLQY, by decorating progressive addition of cations. Specifically, with the sequential addition of Zn, Ag, and Tb into the 3-mercaptopropionic acids capped Au nanoclusters (NCs), the low-frequency vibration of the metal core progressively decreases from 144.
View Article and Find Full Text PDFBiophys Rep (N Y)
January 2025
UCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California at Los Angeles, Los Angeles, CA 90095, USA,; Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA 90095, USA,; Department of Physiology, University of California at Los Angeles, Los Angeles, CA 90095, USA,; California Nano Systems Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA,; Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel.
Membrane potential (MP) changes can provide a simple readout of bacterial functional and metabolic state or stress levels. While several optical methods exist for measuring fast changes in MP in excitable cells, there is a dearth of such methods for absolute and precise measurements of steady-state membrane potentials (MPs) in bacterial cells. Conventional electrode-based methods for the measurement of MP are not suitable for calibrating optical methods in small bacterial cells.
View Article and Find Full Text PDFJ Fluoresc
January 2025
Department of Physics \ Collage of Sciences, University of Kufa, Najaf, Iraq.
This research utilizes density functional theory to investigate the ground and excited-state properties of a new series of organic dyes with D-π-A configurations (D1-D6) for their potential application in dye-sensitized solar cells. The study focuses on modifying these dyes using various functional groups as π-bridges to optimize their electronic properties and improve their efficiency as sensitizers in DSSCs. The frontier molecular orbitals (HOMO and LUMO) were analysed to evaluate electron transfer properties.
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