Red fluorescent proteins (RFPs) are indispensable tools for deep-tissue imaging, fluorescence resonance energy transfer applications, and super-resolution microscopy. Using time-resolved optical spectroscopy this study investigated photoinduced dynamics of three RFPs, KillerRed, mRFP, and DsRed. In all three RFPs, a new transient absorption intermediate was observed, which decays on a microsecond-millisecond time scale. This intermediate is characterized by red-shifted absorption at 1.68-1.72 eV (λmax = 720-740 nm). On the basis of electronic structure calculations, experimental evidence, and published literature, the chemical nature of the intermediate is assigned to an unusual open-shell dianionic chromophore (dianion-radical) formed via photoreduction. A doubly charged state that is not stable in the isolated (gas phase) chromophore is stabilized by the electrostatic field of the protein. Mechanistic implications for photobleaching, blinking, and phototoxicity are discussed.
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http://dx.doi.org/10.1021/jp500919a | DOI Listing |
Anal Chem
January 2025
State Key Laboratory of Applied Organic Chemistry and Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Gansu Lanzhou 730000, China.
The pathogenesis of acute kidney injury (AKI) is a multifaceted process involving various mechanisms, with oxidative stress playing a crucial role in its development. Hypochlorite (HOCl) and cysteine (Cys) are indicators of oxidative stress in AKI pathophysiology, directly reflecting the degree of oxidative stress and disease severity. However, their exact mechanism of action in AKI pathophysiology remains unknown.
View Article and Find Full Text PDFDose Response
January 2025
Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
Cytokinins are plant hormones that regulate cell growth and differentiation. In particular, zeatin (ZTN) delays cellular senescence of human fibroblasts and keratinocytes and exhibits anticancer activity. Chemotherapy-induced anemia is a major side effect of anticancer therapy secondary to premature senescence of red blood cells (RBCs).
View Article and Find Full Text PDFJ Fluoresc
January 2025
Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr Al-Aini Street, Cairo, 11562, Egypt.
Highly sensitive spectrofluorimetric methods were developed for the quantitative estimation of formoterol fumarate dihydrate (FFD) and fluticasone propionate (FP) in both authentic raw materials and marketed dosage forms using a micellar-enhanced spectrofluorimetric approach. The proposed methods are based on the determination of FP in the presence of FFD using the first derivative emission spectrofluorimetry. The peak amplitude of the emission spectra of the formed micellar fluorescence was measured at 465 nm after excitation at 236 nm (λ max of FP).
View Article and Find Full Text PDFChin Med J (Engl)
January 2025
Key Laboratory of Hepatosplenic Surgery, Ministry of Education, Department of Minimal Invasive Hepatic Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, China.
Background: Arsenic trioxide (ATO) is indicated as a broad-spectrum medicine for a variety of diseases, including cancer and cardiac disease. While the role of ATO in hepatic ischemia/reperfusion injury (HIRI) has not been reported. Thus, the purpose of this study was to identify the effects of ATO on HIRI.
View Article and Find Full Text PDFAnal Chem
January 2025
College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, China.
Cancer is a global health challenge that urgently requires more sensitive and effective cancer detection methods. Fluorescence imaging with small molecule fluorescent probes has shown great promise for cancer detection but most of the developed probes lack active tumor cell targeting, which makes them unable to selectively target tumors, thereby reducing the accuracy of in vivo tumor detection. Herein, we report a novel probe that combines a viscosity-sensitive and cell membrane targetable fluorescent group with biotin for targeted imaging and precise visualization of tumor cells and tumors.
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