Andrew A. Jaye
University of East Anglia
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Featured researches published by Andrew A. Jaye.
Journal of the American Chemical Society | 2008
Deborah Stoner-Ma; Andrew A. Jaye; Kate L. Ronayne; Jérome Nappa; Stephen R. Meech; Peter J. Tonge
The neutral form of the chromophore in wild-type green fluorescent protein (wtGFP) undergoes excited-state proton transfer (ESPT) upon excitation, resulting in characteristic green (508 nm) fluorescence. This ESPT reaction involves a proton relay from the phenol hydroxyl of the chromophore to the ionized side chain of E222, and results in formation of the anionic chromophore in a protein environment optimized for the neutral species (the I* state). Reorientation or replacement of E222, as occurs in the S65T and E222Q GFP mutants, disables the ESPT reaction and results in loss of green emission following excitation of the neutral chromophore. Previously, it has been shown that the introduction of a second mutation (H148D) into S65T GFP allows the recovery of green emission, implying that ESPT is again possible. A similar recovery of green fluorescence is also observed for the E222Q/H148D mutant, suggesting that D148 is the proton acceptor for the ESPT reaction in both double mutants. The mechanism of fluorescence emission following excitation of the neutral chromophore in S65T/H148D and E222Q/H148D has been explored through the use of steady state and ultrafast time-resolved fluorescence and vibrational spectroscopy. The data are contrasted with those of the single mutant S65T GFP. Time-resolved fluorescence studies indicate very rapid (< 1 ps) formation of I* in the double mutants, followed by vibrational cooling on the picosecond time scale. The time-resolved IR difference spectra are markedly different to those of wtGFP or its anionic mutants. In particular, no spectral signatures are apparent in the picosecond IR difference spectra that would correspond to alteration in the ionization state of D148, leading to the proposal that a low-barrier hydrogen bond (LBHB) is present between the phenol hydroxyl of the chromophore and the side chain of D148, with different potential energy surfaces for the ground and excited states. This model is consistent with recent high-resolution structural data in which the distance between the donor and acceptor oxygen atoms is < or = 2.4 A. Importantly, these studies indicate that the hydrogen-bond network in wtGFP can be replaced by a single residue, an observation which, when fully explored, will add to our understanding of the various requirements for proton-transfer reactions within proteins.
Photochemistry and Photobiology | 2006
Andrew A. Jaye; Deborah Stoner-Ma; Pavel Matousek; Michael Towrie; Peter J. Tonge; Stephen R. Meech
Abstract The time-resolved emission spectra of wild-type green fluorescent protein (wtGFP) and the T203V GFP mutant have been recorded with picosecond time resolution, allowing the separate characterization of the two spectral components associated with the neutral and anionic forms of the GFP chromophore. Significantly, neither component shifts as a function of time. It is suggested that the absence of spectral shift is a result of highly restricted movement of the protein residues in the vicinity of the chromophore. The shapes of the separated spectra are discussed and their relative ratio analyzed in a steady-state analysis.
Journal of Chemical Physics | 2006
Andrew A. Jaye; Neil T. Hunt; Stephen R. Meech
The ultrafast dynamics of liquid sulphur dioxide have been studied over a wide temperature range and in solution. The optically heterodyne-detected and spatially masked optical Kerr effect (OKE) has been used to record the anisotropic and isotropic third-order responses, respectively. Analysis of the anisotropic response reveals two components, an ultrafast nonexponential relaxation and a slower exponential relaxation. The slower component is well described by the Stokes-Einstein-Debye equation for diffusive orientational relaxation. The simple form of the temperature dependence and the agreement between collective (OKE) and single molecule (e.g., NMR) measurements of the orientational relaxation time suggests that orientational pair correlation is not significant in this liquid. The relative contributions of intermolecular interaction-induced and single-molecule orientational dynamics to the ultrafast part of the spectral density are discussed. Single-molecule librational-orientational dynamics appear to dominate the ultrafast OKE response of liquid SO2. The temperature-dependent OKE data are transformed to the frequency domain to yield the Raman spectral density for the low-frequency intermolecular modes. These are bimodal with the lowest-frequency component arising from diffusive orientational relaxation and a higher-frequency component connected with the ultrafast time-domain response. This component is characterized by a shift to higher frequency at lower temperature. This result is analyzed in terms of a harmonic librational oscillator model, which describes the data accurately. The observed spectral shifts with temperature are ascribed to increasing intermolecular interactions with increasing liquid density. Overall, the dynamics of liquid SO2 are found to be well described in terms of molecular orientational relaxation which is controlled over every relevant time range by intermolecular interactions.
Chemical Physics Letters | 2003
Neil T. Hunt; Andrew A. Jaye; Stephen R. Meech
Abstract The isotropic response of CS2 has been observed by polarisation-resolved ultrafast Raman spectroscopy. The effects of dilution and dispersion in a microemulsion are investigated. The data are contrasted with measurements of the anisotropic response. Previously noted similarities in the relaxation dynamics of the two responses are not preserved on dilution. A simple collision-induced model successfully reproduces the form and timescale of the dynamics, but not the influence of dilution. In all cases the isotropic response of the microemulsion differs from that of the liquid, suggesting the technique has potential to investigate dynamics in complex fluids.
Journal of the American Chemical Society | 2005
Deborah Stoner-Ma; Andrew A. Jaye; Pavel Matousek; Michael Towrie; Stephen R. Meech; Peter J. Tonge
Physical Chemistry Chemical Physics | 2007
Neil T. Hunt; Andrew A. Jaye; Stephen R. Meech
Journal of Physical Chemistry B | 2004
Neil T. Hunt; Andrew A. Jaye; Alexander Hellman; Stephen R. Meech
Journal of Physical Chemistry B | 2003
Neil T. Hunt; Andrew A. Jaye; Stephen R. Meech
Chemical Physics | 2008
Deborah Stoner-Ma; Andrew A. Jaye; Kate L. Ronayne; Jérome Nappa; Peter J. Tonge; Stephen R. Meech
Langmuir | 2005
Andrew A. Jaye; Neil T. Hunt; Stephen R. Meech