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AIMD maps GFP's excited-state proton shuttle
TD-DFT AIMD and wavelet spectra show GFP ESPT is concerted once low-frequency chromophore modes planarize the H-bond wire.
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What is GFP's ESPT product I* known for?
Anionic chromophore emitting around 508 nm.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
Which residues make the proton wire?
Chromophore phenolic OH, crystallographic water, Ser205, then Glu222.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
How many S1 AIMD runs showed ESPT?
Four of five trajectories within one picosecond; one run crashed early.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
How fast is ESPT in trajectory I?
720 fs, concerted and almost synchronous.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
When do S1 O–O distances first shorten vs S0?
About 15–20 fs after excitation, especially contacts to water.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
What happens to O–H stretching frequencies in S1?
They redshift; harmonic Otyr–Htyr falls from 3330 to 3108 cm–1.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
What FSRS pattern do C–O and C–N wavelets match?
Out-of-phase beats with ~250 fs between intense peaks.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
Which low-frequency mode planarizes the wire?
Collective twist/out-of-plane modes near 110–130 cm–1; a twist redshifts 146→101 cm–1.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
What does His148 do near the ESPT?
Hhis148–Otyr drops below 2 Å, helping solvate the nascent anion.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
Are TRJII–IV the same mechanism?
Yes—concerted, slightly asynchronous ESPT at 350, 380 and 980 fs after chromophore/wire rearrangement.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
What ONIOM levels were used?
B3LYP/6-31+G(d,p) for S0 and TD-CAM-B3LYP/6-31+G(d,p) for S1; AMBER MM.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified
How long was the S0 AIMD sampling?
7 ps with a 0.5 fs time step from PDB 1GFL.
Source: The mechanism of a green fluorescent protein proton shuttle unveiled in the time-resolved frequency domain by excited state <i>ab initio</i> dynamics · DOI · quote verified