Revealing of Saccharomyces cerevisiae Yeast Cell Wall Proteins Capable of Binding Thioflavin T, a Fluorescent Dye Specifically Interacting with Amyloid Fibrils

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A. A. Gorkovskii^1*, E. E. Bezsonov², T. A. Plotnikova², T. S. Kalebina², and I. S. Kulaev^1,2

¹Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, pr. Nauki 5, 142290 Pushchino, Moscow Region, Russia; fax: (495) 939-4658; E-mail: anton85ster@gmail.com

²Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; fax: (495) 939-4658; E-mail: kalebina@genebee.msu.ru

^* To whom correspondence should be addressed.

Received September 29, 2008; Revision received December 12, 2008

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Proteins binding thioflavin T leading to its specific fluorescence were discovered in a fraction of noncovalently bound Saccharomyces cerevisiae yeast cell wall mannoproteins. Thioflavin-binding proteins display high resistance to trypsin digestion in solution. These data are the first experimental evidence for the presence of proteins whose properties are characteristic of amyloids in yeast cell wall, except for data on glucanotransferase Bgl2p that has amyloid properties. Our data suggest the anchoring of these proteins in the cell wall by a trypsin-sensitive part of the protein molecule. Experiments with a mutant strain devoid of the BGL2 gene suggest the compensation of absent amyloid-like protein Bgl2p by increase in contents of thioflavin-binding proteins in the cell wall.

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KEY WORDS: thioflavin T, amyloid, yeast cell wall protein, Bgl2p, Saccharomyces cerevisiae

DOI: 10.1134/S0006297909110066

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