Solvent dependence of excited-state proton transfer from pyranine-derived photoacids

Spies, Claudia; Shomer, Shay; Finkler, Björn; Pines, Dina; Pines, Ehud; Jung, Gregor; Huppert, Dan

doi:10.1039/c3cp55292f

Cited by 72 publications

(109 citation statements)

References 72 publications

(129 reference statements)

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“…A stronger photoacid is more likely to undergo ESPT. Our finding is in line with the works of Jung and coworkers (38,39), who observed an increase in the photoacid strength upon modifications of the HPTS sulfonic groups. C 12 -HPTS was tethered to the membrane (at a ratio of 1:100 probe/lipid; Materials and Methods), which was composed of the following lipids: 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-1′-rac-glycerol (POPG), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (POPA), or 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP).…”

Section: Resultssupporting

confidence: 94%

Exploring fast proton transfer events associated with lateral proton diffusion on the surface of membranes

Amdursky

Lin

Aho

et al. 2019

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

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Proton diffusion (PD) across biological membranes is a fundamental process in many biological systems, and much experimental and theoretical effort has been employed for deciphering it. Here, we report on a spectroscopic probe, which can be tightly tethered to the membrane, for following fast (nanosecond) proton transfer events on the surface of membranes. Our probe is composed of a photoacid that serves as our light-induced proton source for the initiation of the PD process. We use our probe to follow PD, and its pH dependence, on the surface of lipid vesicles composed of a zwitterionic headgroup, a negative headgroup, a headgroup that is composed only from the negative phosphate group, or a positive headgroup without the phosphate group. We reveal that the PD kinetic parameters are highly sensitive to the nature of the lipid headgroup, ranging from a fast lateral diffusion at some membranes to the escape of protons from surface to bulk (and vice versa) at others. By referring to existing theoretical models for membrane PD, we found that while some of our results confirm the quasi-equilibrium model, other results are in line with the nonequilibrium model.

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Section: Resultssupporting

confidence: 94%

Exploring fast proton transfer events associated with lateral proton diffusion on the surface of membranes

Amdursky

Lin

Aho

et al. 2019

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

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“…At first, we fitted the curves of the free photoacids in the buffered solution to extract the a value, which we estimated to be 4 Å. This value is smaller than the common values for the pyranine photoacid that are in the range of 6–7 Å 16, 23, 32 , which is reasonable due to the smaller molecular size of the 2-naphthol based photoacids. Since the molecules are free in the bulk aqueous solution, we fixed the dimensionality of the proton diffusion to 3, and the diffusion constant (D) to 9 × 10 −5 cm 2 /s, which is a common value for the diffusion of protons in water.…”

Section: Resultsmentioning

confidence: 95%

Exploring the binding sites and proton diffusion on insulin amyloid fibril surfaces by naphthol-based photoacid fluorescence and molecular simulations

Amdursky

Rashid

Stevens

et al. 2017

Sci Rep

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The diffusion of protons along biological surfaces and the interaction of biological structures with water are fundamental areas of interest in biology and chemistry. Here, we examine the surface of insulin amyloid fibrils and follow the binding of small molecules (photoacids) that differ according to the number and location of their sulfonic groups. We use transient fluorescence combined with a spherically-symmetric diffusion theory to show that the binding mode of different photoacids determines the efficiency of proton dissociation from the photoacid and the dimensionality of the proton’s diffusion. We use molecular dynamics simulations to examine the binding mode and mechanism of the photoacids and its influence on the unique kinetic rates and diffusion properties of the photoacid’s dissociated proton, where we also suggest a proton transfer process between one of the photoacids to proximal histidine residues. We show that the photoacids can be used as fluorescent markers for following the progression of amyloidogenic processes. The detailed characterisation of different binding modes to the surface of amyloid fibrils paves the way for better understanding of the binding mechanism of small molecules to amyloid fibrils.

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“…This is quite expected, since during the gel‐to‐liquid crystalline phase transition, the permeability of molecules towards the hydrophobic core increases, leading to greater population of TDMPP‐OH* (Figure c). However, the change was less prominent with blends having higher percentages of cholesterol, which might be due to cholesterol‐mediated broadening of the gel‐to‐liquid crystalline phase transition …”

Section: Resultsmentioning

confidence: 98%

Modulation of Excited‐State Proton‐Transfer Dynamics inside the Nanocavity of Microheterogeneous Systems: Microenvironment‐Sensitive Förster Energy Transfer to Riboflavin

et al. 2019

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The excited‐state proton‐transfer efficiency of a tetraarylpyrene derivative, 1,3,6,8‐tetrakis(4‐hydroxy‐2,6‐dimethylphenyl)pyrene (TDMPP), was investigated thoroughly in the presence of various surfactant assemblies, such as micelles and vesicles. The confined microheterogeneous environments can significantly retard the extent of the excited‐state proton‐transfer process, resulting in a distinguishable optical signal compared to that in the bulk medium. Physical characteristics of the surfactant assemblies, such as order, interfacial hydration, and surface charge, influence the proton transfer process and allow multiparametric sensing. A higher degree of interfacial hydration facilitates the proton‐transfer process, while the positively charged head groups of the surfactants specifically stabilize the anionic form of the probe (TDMPP−O*). Furthermore, Forster energy transfer from the probe to riboflavin was studied in a phospholipid membrane, wherein the relative ratio of the neutral versus anionic forms (TDMPP‐OH/TDMPP−O*) was found to influence the extent of energy transfer. Overall, we demonstrate how an ultrafast photophysical process, that is, the excited‐state proton transfer, can be influenced by the microenvironment.

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Solvent dependence of excited-state proton transfer from pyranine-derived photoacids

Cited by 72 publications

References 72 publications

Exploring fast proton transfer events associated with lateral proton diffusion on the surface of membranes

Exploring fast proton transfer events associated with lateral proton diffusion on the surface of membranes

Exploring the binding sites and proton diffusion on insulin amyloid fibril surfaces by naphthol-based photoacid fluorescence and molecular simulations

Modulation of Excited‐State Proton‐Transfer Dynamics inside the Nanocavity of Microheterogeneous Systems: Microenvironment‐Sensitive Förster Energy Transfer to Riboflavin

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