Two-photon fluorescence excitation spectra of aromatic amino acids

Abstract Two-photon excited fluorescence excitation spectra using circularly and linearly polarized light are presented for the aromatic amino acids tryptophan, tyrosine (amide form) and phenylalanine in neutral aqueous solution at room temperature. The wave-length range was 440–620 nm, corresponding to 220–310 nm in the UV. In contrast to one-photon (UV) excitation, phenylalanine absorption is about the same as that of tyrosine and both are shifted about 1500 cm −1 to higher energy relative to their UV bands. Thus, observing phenylalanine photophysics in proteins may be more feasible with two-photon excitation. Semiempirical theory gives a good account of the results.

[1]  W. M. McClain,et al.  Two-Photon Molecular Electronic Spectroscopy , 1980 .

[2]  Patrik R. Callis,et al.  A power‐squared sensor for two‐photon spectroscopy and dispersion of second‐order coherence , 1988 .

[3]  Michael C. Zerner,et al.  An intermediate neglect of differential overlap technique for spectroscopy: Pyrrole and the azines , 1973 .

[4]  David M. Sammeth,et al.  1La transitions of jet-cooled 3-methylindole , 1992 .

[5]  M. Wilchek,et al.  Fluorescence studies with tyrosyl peptides. , 1968, Biochemistry.

[6]  David M. Sammeth,et al.  Two-photon fluorescence excitation spectra of indole in vapor and jet: 1La states , 1990 .

[7]  W. M. McClain.  Excited State Symmetry Assignment Through Polarized Two‐Photon Absorption Studies of Fluids , 1971 .

[8]  P. Callis.  Two-photon properties of the La and Lb bands of substituted benzenes computed from CNDO/S , 1984 .

[9]  Richard D. Jones,et al.  Two-photon spectra of inductively perturbed naphthalenes , 1988 .

[10]  P. Callis,et al.  Resolution of La and Lb bands in methyl indoles by two-photon spectroscopy , 1987 .

[11]  T. W. Scott,et al.  Perturbation selection rules for multiphoton electronic spectroscopy of neutral alternant hydrocarbonsa) , 1983 .

[12]  W. Denk,et al.  Two-photon laser scanning fluorescence microscopy. , 1990, Science.

[13]  David M. Sammeth,et al.  Two-photon fluorescence excitation spectrum of a naphthalene norbornylog: Implications for electron transfer , 1990 .

[14]  Shou-Ping Jiang,et al.  Two-photon excitation of proteins , 1984 .

[15]  J. Petruska.  Changes in the Electronic Transitions of Aromatic Hydrocarbons on Chemical Substitution. II. Application of Perturbation Theory to Substituted‐Benzene Spectra , 1961 .

[16]  P. Callis.  Molecular orbital theory of the 1Lb and 1La states of indole , 1991 .

[17]  J. Frisoli,et al.  Anisotropy spectra of indole and N-acetyl-L-tryptophanamide observed for two-photon excitation of fluorescence , 1992 .

[18]  Joseph R. Lakowicz,et al.  Time-resolved laser spectroscopy in biochemistry II , 1990 .

[19]  J. Lakowicz,et al.  Tryptophan fluorescence intensity and anisotropy decays of human serum albumin resulting from one-photon and two-photon excitation. , 1992, Biophysical chemistry.

[20]  B. Valeur,et al.  RESOLUTION OF THE FLUORESCENCE EXCITATION SPECTRUM OF INDOLE INTO THE 1La AND 1Lb EXCITATION BANDS * , 1977, Photochemistry and photobiology.

[21]  Maurice R. Eftink,et al.  Photophysics of indole derivatives : experimental resolution of La and Lb transitions and comparison with theory , 1990 .

[22]  Richard D. Jones,et al.  Polarized two-photon fluorescence excitation spectra of indole and benzimidazole , 1986 .

[23]  J. Cable.  Polarization resolved two‐photon resonant ionization spectroscopy of indole and 3‐methylindole , 1990 .