Biomaterial Database

Toward understanding tryptophan fluorescence in proteins. 1998

Y Chen, and M D Barkley

Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7078, USA.

A general approach to dissecting the complex photophysics of tryptophan is presented and used to elucidate the effects of amino acid functional groups on tryptophan fluorescence. We have definitively identified the amino acid side chains that quench tryptophan fluorescence and delineated the respective quenching mechanisms in a simple model system. Steady-state and time-resolved fluorescence techniques, photochemical H-D exchange experiments, and transient absorption techniques were used to measure individual contributions to the total nonradiative rate for deactivation of the excited state, including intersystem crossing, solvent quenching, and excited-state proton and electron transfer rates. Eight amino acid side chains representing six functional groups quench 3-methylindole fluorescence with a 100-fold range in quenching rate constant. Lysine and tyrosine side chains quench by excited-state proton transfer; glutamine, asparagine, glutamic and aspartic acid, cysteine, and histidine side chains quench by excited-state electron transfer. These studies provide a framework for deriving detailed structural and dynamical information from tryptophan fluorescence intensity and lifetime data in peptides and proteins.

UI	MeSH Term	Description	Entries
D010782	Photolysis	Chemical bond cleavage reactions resulting from absorption of radiant energy.	Photodegradation
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D011522	Protons	Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.	Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D005454	Fluorescence Polarization	Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.	Anisotropy, Fluorescence,Fluorescence Anisotropy,Polarization, Fluorescence,Anisotropies, Fluorescence,Fluorescence Anisotropies,Fluorescence Polarizations,Polarizations, Fluorescence
D005998	Glycine	A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.	Aminoacetic Acid,Glycine, Monopotassium Salt,Glycine Carbonate (1:1), Monosodium Salt,Glycine Carbonate (2:1), Monolithium Salt,Glycine Carbonate (2:1), Monopotassium Salt,Glycine Carbonate (2:1), Monosodium Salt,Glycine Hydrochloride,Glycine Hydrochloride (2:1),Glycine Phosphate,Glycine Phosphate (1:1),Glycine Sulfate (3:1),Glycine, Calcium Salt,Glycine, Calcium Salt (2:1),Glycine, Cobalt Salt,Glycine, Copper Salt,Glycine, Monoammonium Salt,Glycine, Monosodium Salt,Glycine, Sodium Hydrogen Carbonate,Acid, Aminoacetic,Calcium Salt Glycine,Cobalt Salt Glycine,Copper Salt Glycine,Hydrochloride, Glycine,Monoammonium Salt Glycine,Monopotassium Salt Glycine,Monosodium Salt Glycine,Phosphate, Glycine,Salt Glycine, Monoammonium,Salt Glycine, Monopotassium,Salt Glycine, Monosodium
D006639	Histidine	An essential amino acid that is required for the production of HISTAMINE.	Histidine, L-isomer,L-Histidine,Histidine, L isomer,L-isomer Histidine
D000111	Acetylcysteine	The N-acetyl derivative of CYSTEINE. It is used as a mucolytic agent to reduce the viscosity of mucous secretions. It has also been shown to have antiviral effects in patients with HIV due to inhibition of viral stimulation by reactive oxygen intermediates.	Mercapturic Acid,Acemuc,Acetabs,Acetylcystein AL,Acetylcystein Atid,Acetylcystein Heumann,Acetylcystein Trom,Acetylcysteine Hydrochloride,Acetylcysteine Sodium,Acetylcysteine Zinc,Acetylcysteine, (D)-Isomer,Acetylcysteine, (DL)-Isomer,Acetylcysteine, Monoammonium Salt,Acetylcysteine, Monosodium Salt,Acetylin,Acetyst,Acétylcystéine GNR,Airbron,Alveolex,Azubronchin,Bisolvon NAC,Bromuc,Broncho-Fips,Broncholysin,Broncoclar,Codotussyl,Cystamucil,Dampo Mucopect,Eurespiran,Exomuc,Fabrol,Fluimucil,Fluprowit,Frekatuss,Genac,Hoestil,Ilube,Jenacystein,Jenapharm,Lantamed,Larylin NAC,Lindocetyl,M-Pectil,Muciteran,Muco Sanigen,Mucomyst,Mucosil,Mucosol,Mucosolvin,N-Acetyl-L-cysteine,N-Acetylcysteine,NAC AL,NAC Zambon,Optipect Hustengetränk,Siccoral,Siran,Solmucol,acebraus,durabronchal,mentopin Acetylcystein,Acetylcystein, mentopin,Acid, Mercapturic,Broncho Fips,BronchoFips,Hustengetränk, Optipect,Hydrochloride, Acetylcysteine,M Pectil,MPectil,Monoammonium Salt Acetylcysteine,Monosodium Salt Acetylcysteine,Mucopect, Dampo,N Acetyl L cysteine,N Acetylcysteine,NAC, Bisolvon,Sanigen, Muco,Sodium, Acetylcysteine,Zambon, NAC,Zinc, Acetylcysteine
D012862	Skatole		3-Methylindole,3 Methylindole
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence