Phototriggers are useful molecular tools to initiate reactions in enzymes by light for the purpose of photoenzymatic design and mechanistic investigations. Here, we incorporated the non-natural amino acid 5-cyanotryptophan (W5CN) in a polypeptide scaffold and resolved the photochemical reaction of the W5CN-W motif using femtosecond transient UV/Vis and mid-IR spectroscopy. We identified a marker band of ∼2037 cm-1 from the CN stretch of the electron transfer intermediate W5CN·- in the transient IR measurement and found UV/Vis spectroscopic evidence for the W·+ radical at 580 nm. Through kinetic analysis, we characterized that the charge separation between the excited W5CN and W occurs in 253 ps, with a charge-recombination lifetime of 862 ps. Our study highlights the potential use of the W5CN-W pair as an ultrafast phototrigger to initiate reactions in enzymes that are not light-sensitive, making downstream reactions accessible to femtosecond spectroscopic detection.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/5.0143384 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A supramolecular approach towards the photorelease of encapsulated caged acids in water: 7-diethylaminothio-4-coumarinyl molecules as triggers.
Photochem Photobiol Sci
November 2024
Department of Chemistry, University of Miami, Coral Gables, FL, 33146, USA.
Herein, we establish the release of aliphatic acids in water upon excitation of 7-diethylaminothio-4-coumarinyl derivatives encapsulated within the organic host octa acid (OA). The 7-diethylaminothio-4-coumarinyl skeleton, employed here as the trigger, photoreleases caged molecules from the excited triplet state, in contrast to its carbonyl analogue, where the same reaction is known to occur from the excited singlet state. Encapsulation in OA solubilizes molecules in water that are otherwise water-insoluble, and retains the used trigger within itself following the release of the aliphatic acid.
View Article and Find Full Text PDFFemtosecond to Microsecond Observation of Photochemical Pathways in Nitroaromatic Phototriggers Using Transient Absorption Spectroscopy.
J Phys Chem A
July 2024
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K.
The synthetic accessibility and tolerance to structural modification of phototriggered compounds (PTs) based on the - nitrobenzene (ONB) protecting group have encouraged a myriad of applications including optimization of biological activity, and supramolecular polymerization. Here, a combination of ultrafast transient absorption spectroscopy techniques is used to study the multistep photochemistry of two nitroaromatic phototriggers based on the ONB chromophore, -(4,5-dimethoxy-2-nitrobenzyl)-l-serine (DMNB-Ser) and [(2-nitrophenyl)methyl]-l-tyrosine hydrochloride (NB-Tyr), in DMSO solutions on femtosecond to microsecond time scales following the absorption of UV light. From a common -S excited state, the PTs can either undergo excited state intramolecular hydrogen transfer (ESIHT) to an -S isomer within the singlet state manifold, leading to direct S → S internal conversion through a conical intersection, or competitive intersystem crossing (ISC) to access the triplet state manifold on time scales of (1.
View Article and Find Full Text PDFA billion years of evolution manifest in nanosecond protein dynamics.
Proc Natl Acad Sci U S A
March 2024
Department of Chemistry, University of Zurich, Zurich 8057, Switzerland.
Protein dynamics form a critical bridge between protein structure and function, yet the impact of evolution on ultrafast processes inside proteins remains enigmatic. This study delves deep into nanosecond-scale protein dynamics of a structurally and functionally conserved protein across species separated by almost a billion years, investigating ten homologs in complex with their ligand. By inducing a photo-triggered destabilization of the ligand inside the binding pocket, we resolved distinct kinetic footprints for each homolog via transient infrared spectroscopy.
View Article and Find Full Text PDFAn ultrafast phototrigger of the Trp5CN-Trp motif in a β-hairpin peptide.
J Chem Phys
May 2023
Center for Ultrafast Science and Technology, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Phototriggers are useful molecular tools to initiate reactions in enzymes by light for the purpose of photoenzymatic design and mechanistic investigations. Here, we incorporated the non-natural amino acid 5-cyanotryptophan (W5CN) in a polypeptide scaffold and resolved the photochemical reaction of the W5CN-W motif using femtosecond transient UV/Vis and mid-IR spectroscopy. We identified a marker band of ∼2037 cm-1 from the CN stretch of the electron transfer intermediate W5CN·- in the transient IR measurement and found UV/Vis spectroscopic evidence for the W·+ radical at 580 nm.
View Article and Find Full Text PDFPhotothermal motion: effect of low-intensity irradiation on the thermal motion of organic nanoparticles.
Nanoscale
May 2022
Department of Chemistry "Giacomo Ciamician", University of Bologna, Via Selmi 2, Bologna 40126, Italy.
The effect of local photo-triggered heat release on the motion of organic nanopartcles (NP), a process that is itself thermal, is largely unexplored under low-intensity irradiation. Here, we develop organic NP specifically tailored for this study and demonstrate, comparing three different irradiation intensity regimes, that indeed the NP undergo "acceleration" upon light absorption (Photothermal Motion). These NP have a well-defined chemical composition and extremely high molar absorbance coefficient, and upon excitation, they deactivate mostly non radiatively with localized heat dissipation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!