Tryptophan and Non-Tryptophan Fluorescence of the Eye Lens Proteins Provides Diagnostics of Cataract at the Molecular Level
| Autor: | Nicola M. Howarth, Rory R. Duncan, Kim K. Buttenschön, Dmitry M. Gakamsky, Daniel J. Daly, Anna Gakamsky, Baljean Dhillon |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
medicine.medical_specialty genetic structures Swine Ultraviolet Rays Peptide Biology Mass spectrometry Cataract Fluorescence Mass Spectrometry Article Lens protein 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Ophthalmology Lens Crystalline medicine Journal Article Animals Humans Emission spectrum Spectroscopy Chromatography High Pressure Liquid chemistry.chemical_classification Multidisciplinary Tryptophan Crystallins eye diseases Spectrometry Fluorescence 030104 developmental biology chemistry 030221 ophthalmology & optometry Biophysics Protein Processing Post-Translational Kynurenine |
| Zdroj: | Gakamsky, A, Duncan, R R, Howarth, N M, Dhillon, B, Buttenschön, K K, Daly, D J & Gakamsky, D 2017, ' Tryptophan and Non-Tryptophan Fluorescence of the Eye Lens Proteins Provides Diagnostics of Cataract at the Molecular Level ', Scientific Reports, vol. 7, pp. 40375 . https://doi.org/10.1038/srep40375 Scientific Reports |
| Popis: | The chemical nature of the non-tryptophan (non-Trp) fluorescence of porcine and human eye lens proteins was identified by Mass Spectrometry (MS) and Fluorescence Steady-State and Lifetime spectroscopy as post-translational modifications (PTM) of Trp and Arg amino acid residues. Fluorescence intensity profiles measured along the optical axis of human eye lenses with age-related nuclear cataract showed increasing concentration of fluorescent PTM towards the lens centre in accord with the increased optical density in the lens nucleolus. Significant differences between fluorescence lifetimes of “free” Trp derivatives hydroxytryptophan (OH-Trp), N-formylkynurenine (NFK), kynurenine (Kyn), hydroxykynurenine (OH-Kyn) and their residues were observed. Notably, the lifetime constants of these residues in a model peptide were considerably greater than those of their “free” counterparts. Fluorescence of Trp, its derivatives and argpyrimidine (ArgP) can be excited at the red edge of the Trp absorption band which allows normalisation of the emission spectra of these PTMs to the fluorescence intensity of Trp, to determine semi-quantitatively their concentration. We show that the cumulative fraction of OH-Trp, NFK and ArgP emission dominates the total fluorescence spectrum in both emulsified post-surgical human cataract protein samples, as well as in whole lenses and that this correlates strongly with cataract grade and age. |
| Databáze: | OpenAIRE |
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