INTERACTION OF THE DYE CONGO RED WITH FIBRILS OF LYSOZYME, BETA2-MICROGLOBULIN AND TRANSTHYRETIN
O.I. Antimonova,1,2,* N.A. Grudinina,1,2 V.V. Egorov,3,4 D.S. Polyakov,1,5
V.V. Iljin,1 M.M. Shavlovsky 1,5
1 Institute of Experimental Medicine, St. Petersburg, 197376, 2 V.A. Almazov Federal North-West Medical Research Centre, Ministry of
Healthcare of the Russian Federaion, St. Petersburg, 197341,
3 Research Institute of Influenza, Ministry of Healthcare of the Russian Federaion, St. Petersburg, 197022,
4 B.P. Konstantinov Petersburg Nuclear Physics Institute, National Research Centre "Kurchatov Institute",
Gatchina, Leningrad district, 188300, and 5 I.I. Mechnikov North-West State Medical University, Ministry of Healthcare of the Russian Federaion,
St. Petersburg, 191015;
* e-mail: oa0584@mail.ru
By means of spectrophotometric assay we investigated interaction of the dye Congo red (CR) with fibrils of model proteins - hen egg white lysozyme, recombinant human
beta2-microglobulin (b2M) and recombinant human transthyretin (TTR). The commercial dye sample was found to contain a significant amount of impurities. Methods for the
dye purification are disclosed and CR molar extinction coefficient at 490 nm (ε490) was determined to be 3.3 · 104 Ì-1
· cm-1 at pH above 6.0. Formation of the CR-fibril complex results in changes in the dye visible absorption spectrum. According to the data on titration of fibril
solutions with excess of the dye, CR binds to lysozyme fibrils at a ratio of about 5 molecules per protein monomer within fibril structure, to b2M fibrils - about 4 molecules per
monomer, to TTR fibrils - about 4 molecules per subunit of the protein.
Key words:
amyloidoses, amyloidogenic proteins, lysozyme, beta2-microglobulin, transthyretin, Congo red, spectrophotometry
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