Raman scattering tensors of tyrosine

Abstract

Polarized Raman scattering measurements have been made of a single crystal of L‐tyrosine by the use of a Raman microscope with the 488.0‐nm exciting beam from an argon ion laser. The L‐tyrosine crystal belongs to the space group P212121 (orthorhombic), and Raman scattering intensities corresponding to the aa, bb, cc, ab and ac components of the crystal Raman tensor have been determined for each prominent Raman band. A similar set of measurements has been made of L‐tyrosine‐d4, in which four hydrogen atoms on the benzene ring are replaced by deuterium atoms. The effects of NH3 → ND3 and OH → OD on the Raman spectrum have also been examined. In addition, depolarization ratios of some bands of L‐tyrosine in aqueous solutions of pH 13 and pH 1 were examined. For comparison with these experimental results, on the other hand, ab initio molecular orbital calculations have been made of the normal modes of vibration and their associated polarizability oscillations of the L‐tyrosine molecule. On the basis of these experimental data and by referring to the results of the calculations, discussions have been presented on the Raman tensors associated to some Raman bands, including those at 829 cm−1 (benzene ring breathing), 642 cm−1 (benzene ring deformation), and 432 cm−1 (Cα‐Cβ‐Cγ bending). © 1998 John Wiley & Sons, Inc. Biospectroscopy 4: 61–71, 1998

Single Molecule Vibrational Fine-structure of Tyrosine Adsorbed on Ag Nano-Crystals

“…The difference between the two is particularly evident in the 1500-1700 cm -1 frequency region, where the Tyr Raman spectrum only shows the mode-pair 8a/8b at 1614/1600 cm -1 whereas the Tyr SERS spectrum exhibits a ~100 cm -1 broad band centered at around 1580 cm -1 . It is well known that deprotonation of Tyr to tyrosinate (TyrO -) results in a softening of 8a/8b to 1601/1558 cm -1 [39,40]. This indicates that tyrosinate is the predominant surface species, as previously concluded by Lee et al [16] and Herne et al [17], and that an inhomogeneous TyrO --Ag surface interaction is an important cause for spectral broadening in Tyr SERS.…”

“…The ratio of recorded counts to collected photons, e was estimated to 1:50 from measurements on a source with known irradiance. Finally, the number of sampled Tyr molecules N was estimated to 1.6 ´ 10 10 , where, we have used a probe volume of (1.5 mm) 3 and a Tyr density [39] of 4.7 ´ 10 9 molecules per mm 3 . Inserting into Eq.…”

“…6. The calculation for free Tyr agrees both with the measured crystalline Tyr spectrum and with previous calculations [39][40][41]. The thiophenol "SERS calculation" was based on a model in which the thiophenol molecule coordinated to a single Ag + -ion through the thiol-group.…”

Molecular characterization of reconstructed skin model by Raman microspectroscopy: Comparison with excised human skin

“…The phenylalanine also contributes to the 1175 and 1339 cm 21 vibrations. 19,25,[38][39][40][41][42][43][44] The presence of tyrosine (Tyr) is highlighted by the 643 cm 21 band (ring breathing) and the Raman doublet at 829 and 851 cm 21 , this doublet is due to Fermi resonance between the ring breathing vibration, and the overtone of the nonplanar ring vibration at 413 cm 21 . The intensity ratio I 829 /I 851 is related to the state of the phenolic hydroxyl group.…”

Differentiation of bacterial strains by means of surface enhanced FT-Raman spectroscopy

“…For instance, the spectral band at 646 cm -1 of bacterial pathogens is assigned to tyrosine skeletal vibration in [8], while in [6] it is assigned to the COO -band of amino acids or C-S stretch mode of cysteine. It is well established that in case of tyrosine water solution the most intense Raman spectral bands are located at 826, 846, 1210, and 1615 cm -1 [9]. There are no bands with intensities higher than intensity of the band at 646 cm -1 in our SERS spectra of the bacterial pathogens in the 820-850 cm -1 region; therefore, this band cannot be attributed to tyrosine.…”