Picosecond studies of the fluorescence probe molecule 8-anilino-1-naphthalenesulfonic acid

Robinson, G. W.; Robbins, Rebecca J.; Fleming, Graham R.; Morris, John; Knight, Alan; Morrison, Richard J. S.

doi:10.1021/ja00491a003

Cited by 92 publications

(72 citation statements)

References 3 publications

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“…To further elucidate the nature of the spectral shift we also measured the time-resolved anisotropy, r(t). At t ϭ 0, r(t) ϭ 0.32 and decays to the base line with ϭ 58 ps, the rotational relaxation time of ANS in methanol; in water was found to be 70 ps (30). Most importantly, the r(t) decay in methanol is on a much different time scale than that of solvation; conformational changes (which should alter the anisotropy) to yield the CT state are separable in their time scale from that of solvation (23).…”

Section: Fig 2 (Upper)mentioning

confidence: 99%

Ultrafast surface hydration dynamics and expression of protein functionality: α-Chymotrypsin

Pal

Peón

Zewail

2002

Proc. Natl. Acad. Sci. U.S.A.

118

138

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We report studies of hydration dynamics at the surface of the enzyme protein bovine pancreatic ␣-chymotrypsin. The probe is the well known 1-anilinonaphthalene-8-sulfonate, which binds selectively in the native state of the protein, not the molten globule, as shown by x-ray crystallography. With femtosecond time resolution, we examined the hydration dynamics at two pHs, when the protein is physiologically in the inactive state (pH 3.6) or the active state (pH 6.7); the global structure and the binding site remain the same. The hydration correlation function, C(t), whose decay is governed by the rotational and translational motions of water molecules at the site, shows the behavior observed in this laboratory for other proteins, Subtilisin Carlsberg and Monellin, using the intrinsic amino acid tryptophan as a probe for surface hydration. However, the time scales and amplitudes vary drastically at the two pHs. For the inactive protein state, C(t) decays with an ultrafast component, close to bulk-type behavior, but 50% of the C(t) decays at a much slower rate, ‫؍‬ 43 ps. In contrast, for the active state, the ultrafast component becomes dominant (90%) and the slow component changes to a faster decay, ‫؍‬ 28 ps. These results indicate that in the active state water molecules in the hydration layer around the site have a high degree of mobility, whereas in the inactive state the water is more rigidly structured. For the substrate-enzyme complex, the function and dynamics at the probe site are correlated, and the relevance to the enzymatic action is clear.A lmost all biological macromolecules (proteins, enzymes, and DNA) are inactive in the absence of water. The hydration shell formed by water molecules in close vicinity of a protein͞ enzyme is particularly important for the stability of the structure and the function or recognition at a specific site. This role of hydration in enzyme catalysis is well known and has recently been reviewed in a number of publications (see, e.g., refs. 1-3). In one of these studies it was shown that the dehydration of a protein, which makes it more rigid and increases its denaturation temperature, is correlated with the loss of its physiological function (1). An understanding of the dynamics of water molecules at the surface of the protein, with spatial molecular and temporal femtosecond resolution of a single site, is important for elucidating a molecular picture and was the goal of a series of publications from this laboratory (4-6).Using the intrinsic single-tryptophan amino acid as a probe (4, 5), we found that the hydration dynamics at the surface of two different proteins, Subtilisin Carlsberg (SC) (4) and Monellin (5), occur on two well separated time scales: 800 fs and 38 ps for SC and 1.3 ps and 16 ps for Monellin. The slow and fast components are of similar magnitude. From these results, we discussed two types of water hydration trajectories: one fast, bulk type and another much slower, surface-bound type. When these experiments were made on a probe away from the surface by Ϸ1...

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Section: Fig 2 (Upper)mentioning

confidence: 99%

Ultrafast surface hydration dynamics and expression of protein functionality: α-Chymotrypsin

Pal

Peón

Zewail

2002

Proc. Natl. Acad. Sci. U.S.A.

118

138

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“…The 1 H NMR spectra of the RTIL [P 6,6,6,14 ][ANS] in deuterated solvent showed two separate spectral windows: one (4 to 0 ppm) containing peaks of the aliphatic protons from the long alkyl chain of the [P 6,6,6,14 ] cation with a pattern which was, in all samples, similar to that appearing for the starting pure [P 6,6,6,14 ] [Cl]; and the other (9 to 6 ppm) displaying the aromatic protons from the ANS anion structure. The ratio of the integrated intensities of the , are linearly correlated with the solvent viscosity divided by temperature (h/T) in the heating cycle, but in the cooling cycle the widths are larger, as if the pure IL had a higher local viscosity.…”

Section: Nmr Studiesmentioning

confidence: 99%

“…UV/Vis absorption spectroscopy and emission spectroscopy studies [P 6,6,6,14 ][ANS] was dissolved in acetonitrile and methanol, enabling the measurement of the absorption spectra (see Table 1 and Figure 4). The results are similar to those reported previously for ANS sodium salts.…”

Section: Nmr Studiesmentioning

confidence: 99%

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Characterization of a Novel Intrinsic Luminescent Room‐Temperature Ionic Liquid Based on [P_6,6,6,14][ANS]

Delgado

Raymundo

Vilarigues

et al. 2014

Chemistry A European J

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Intrinsically luminescent room-temperature ionic liquids (RTILs) can be prepared by combining a luminescent anion (more common) or cation with appropriate counter ions, rendering new luminescent soft materials. These RTILs are still new, and many of their photochemical properties are not well known. A novel intrinsic luminescent RTIL based on the 8-anilinonaphthalene-1-sulfonate ([ANS]) anion combined with the trihexyltetradecylphosphonium ([P6,6,6,14 ]) cation was prepared and characterized by spectroscopic techniques. Detailed photophysical studies highlight the influence of the ionic liquid environment on the ANS fluorescence, which together with rheological and (1) H NMR experiments illustrate the effects of both the viscosity and electrostatic interactions between the ions. This material is liquid at room temperature and possesses a glass transition temperature (Tg ) of 230.4 K. The fluorescence is not highly sensitive to factors such as temperature, but owing to its high viscosity, dynamic Stokes shift measurements reveal very slow components for the IL relaxation.

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“…These pre-exponential factors can be used to calculate the fraction of ANS bound to site 1 and site 2 (Robinson et al 1978, Kosower, Kanety 1983 Table 3.3. The differential angle plots show a transition towards negative values at high modulation frequencies.…”

Section: Resultsmentioning

confidence: 99%

Protein-Ligand Interactions and Allosteric Regulation of Activity in DREAM Protein

González¹

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Picosecond studies of the fluorescence probe molecule 8-anilino-1-naphthalenesulfonic acid

Cited by 92 publications

References 3 publications

Ultrafast surface hydration dynamics and expression of protein functionality: α-Chymotrypsin

Ultrafast surface hydration dynamics and expression of protein functionality: α-Chymotrypsin

Characterization of a Novel Intrinsic Luminescent Room‐Temperature Ionic Liquid Based on [P_6,6,6,14][ANS]

Protein-Ligand Interactions and Allosteric Regulation of Activity in DREAM Protein

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Picosecond studies of the fluorescence probe molecule 8-anilino-1-naphthalenesulfonic acid

Cited by 92 publications

References 3 publications

Ultrafast surface hydration dynamics and expression of protein functionality: α-Chymotrypsin

Ultrafast surface hydration dynamics and expression of protein functionality: α-Chymotrypsin

Characterization of a Novel Intrinsic Luminescent Room‐Temperature Ionic Liquid Based on [P6,6,6,14][ANS]

Protein-Ligand Interactions and Allosteric Regulation of Activity in DREAM Protein

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Characterization of a Novel Intrinsic Luminescent Room‐Temperature Ionic Liquid Based on [P_6,6,6,14][ANS]