Near Uv Optical 2nd-Harmonic Generation Studies of Surface-Adsorbed Tryptophan Residues
- Journal Article
A new optical method intended for interfacial protein studies has surfaced from the observation of near UV second harmonic generation (SHG) from the aromatic amino acids. Here, the first hyperpolarizability, β=4.72±0.52×10−30 esu, of t‐butyloxycarbonyl‐L‐tryptophan is measured for SHG at 266 nm, and its polar orientation at the air–water interface is deduced. The indole ring nitrogen atom is found to point upwards at the interface. From a monolayer surface density of 1.74±0.15 adsorbate molecules/nm2, it is estimated that a minimum of 0.49 Trp residues/nm2 of surface area can be detected above the water background for this wavelength. SHG studies of tryptophan‐containing peptides and proteins based on these results have the potential to complement existing linear optical techniques by providing new information on interfacial molecular ordering. Show more
Journal / seriesThe Journal of Chemical Physics
Pages / Article No.
PublisherAmerican Institute of Physics
Organisational unit03640 - Vogel, Viola / Vogel, Viola
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