Tryptophan mutants of human C5a anaphylatoxin: A fluorescence anisotropy decay and energy transfer study
| Autor: | Jörg Köhl, Wilfried Bautsch, Andreas Klos, T. Melcher, M. Federwisch, Monica Emde, Axel Wollmer, T. Stühmer |
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| Rok vydání: | 1993 |
| Předmět: |
Anaphylatoxins
Circular dichroism Time Factors Molecular Sequence Data Biophysics Fluorescence spectrometry Analytical chemistry Complement C5a Fluorescence Polarization Biochemistry Naphthalenesulfonates Side chain Humans Amino Acid Sequence Cysteine Rotational correlation time Fluorescent Dyes Chemistry Circular Dichroism Sulfhydryl Reagents Organic Chemistry Tryptophan Fluorescence Recombinant Proteins Crystallography Energy Transfer Mutation Helix Spectrophotometry Ultraviolet Fluorescence anisotropy |
| Zdroj: | Biophysical Chemistry. 46:237-248 |
| ISSN: | 0301-4622 |
| Popis: | Three mutants of the anaphylatoxin C5a were prepared with positions 2, 64 and 70, respectively, substituted by tryptophan. The last mutant was additionally labelled at Cys27 for fluorescence energy transfer (FET) measurements. The structural integrity and biological activity of the molecules were not affected. Fluorescence anisotropy decay (FAD) measurements showed that the rotational correlation time for tryptophan decreases in the order: [Trp2]rhC5a > [Trp64]rhC5a > [Trp70]rhC5a, indicating an increasing mobility of the side chain. Measurements of the fluorescence energy transfer from Trp70 to the 1,5-AEDANS group at Cys27 yielded a distance distribution of 2.4 +/- 0.8 nm. This value is compatible with the C-terminal chain being arranged as a slightly stretched helix pointing away from the body of the molecule. |
| Databáze: | OpenAIRE |
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