Amyloidogenic peptides of yeast cell wall glucantransferase Bgl2p as a model for the investigation of its pH-dependent fibril formation

Abstract

The pH-dependence of the ability of Bgl2p to form fibrils was studied using synthetic peptides with potential amyloidogenic determinants (PADs) predicted in the Bgl2p sequence. Three PADs, FTIFVGV, SWNVLVA and NAFS, were selected on the basis of combination of computational algorithms. Peptides AEGFTIFVGV, VDSWNVLVAG and VMANAFSYWQ, containing these PADs, were synthesized. It was demonstrated that these peptides had an ability to fibrillate at pH values from 3.2 to 5.0. The PAD-containing peptides, except for VDSWNVLVAG, could fibrillate also at pH values from pH 5.0 to 7.6. We supposed that the ability of Bgl2p to form fibrils most likely depended on the coordination of fibrillation activity of the PAD-containing areas and Bgl2p could fibrillate at mild acid and neutral pH values and lose the ability to fibrillate with the increasing of pH values. It was demonstrated that Bgl2p was able to fibrillate at pH value 5.0, to form fibrils of various morphology at neutral pH values and lost the fibrillation ability at pH value 7.6. The results obtained allowed us to suggest a new simple approach for the isolation of Bgl2p from Saccharomyces cerevisiae cell wall.

Keywords: :

• yeast cell wall
• amyloid
• glucantransferase
• Bgl2p
• thioflavin T

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

This work was funded by the Carl Zeiss Program for Support of Research Work of Young Investigators from Higher Education Institutions of Russia (Grant no. MSU 16/11CZ), the Drug Research Academy (Faculty of Pharmaceutical Sciences, University of Copenhagen), the Russian Foundation for Basic Research (Grant no. 09-04-00768-a, 10-04-01821a, 11-04-763a, 12-04-31966-mol_a), the programs “Molecular and Cellular Biology” (01200959110 and 01200957492) and “Fundamental Sciences to Medicine,” Howard Hughes Medical Institute (55005607), the Federal Agency for Science and Innovation (grant no. 02.740.11.0295 and 16.740.11.0478) and by the German organization DAAD (German Academic Exchange Service) in the frame of a Scientific Cooperation Agreement between Moscow and Rostock Universities. The authors would like to acknowledge associate professor Osman Mirza (Faculty of Health and Medical Sciences, University of Copenhagen) for providing access to facilities useful for growing yeast, professor Per Amstrup Pedersen (Department of Biology, University of Copenhagen) for the BMA64-1B strain, Stefano Colombo (Faculty of Health and Medical Sciences, University of Copenhagen) for discussion of the results obtained, Dr S.N. Egorova and Dr M.N. Zhmak (Institute of Bioorganic Chemistry, Moscow, Russia) for synthesis of the peptides, and Dr Annette E. Langkilde (Faculty of Health and Medical Sciences, University of Copenhagen) for collecting the X-ray fiber diffraction data. We are grateful to Tatyana A. Sabirzyanova for the discussion of our results and to Aleksandra Zhukova for the assistance in preparing of manuscript.

Notes

† Current affiliation: Laboratory of Biochemistry and Genetics; National Institute of Diabetes and Digestive and Kidney Disease; National Institutes of Health; Bethesda, MD USA