In this dissertation, excited state proton transfer (ESPT) and its inhibition in solution and protein environments are revealed using both femtosecond transient absorption (fs-TA) spectroscopy and femtosecond stimulated Raman spectroscopy (FSRS). Using a tunable Raman pump to enhance transient vibrational features of the photoacidic chromophore HPTS in methanol and methanol...
Imaging Ca²⁺ dynamics in living systems holds great
potential to advance neuroscience and cellular biology. G-GECO1.1
is an intensiometric fluorescent protein Ca²⁺-biosensor with a Thr-Tyr-Gly chromophore. The protonated chromophore emits green
upon photoexcitation via excited-state proton transfer (ESPT). Upon
Ca²⁺ binding, a significant population of the chromophores becomes
deprotonated. It...
Fluorescent proteins (FPs) are luminescent biomolecules that emit characteristic hues upon irradiation. A group of calmodulin (CaM)-green FP (GFP) chimeras have been previously engineered to enable the optical detection of calcium ions (Ca²⁺). We investigate one of these genetically encoded Ca²⁺ biosensors for optical imaging (GECOs), GEM-GECO1, which fluoresces green...
Fluorescent proteins (FPs) have played a pivotal role in bioimaging and advancing biomedicine. The versatile fluorescence from engineered, genetically encodable FP variants greatly enhances cellular imaging capabilities, which are dictated by excited state structural dynamics of the embedded chromophore inside the protein pocket. Visualization of the molecular choreography of the...