Chairman, Department of Biophysics and Radiation Biology
Vice Rector for Education and International Affairs, Semmelweis University (HU)
Miklós Kellermayer is the chairman of the Department of Biophysics and Radiation Biology and Vice Rector for Education and International Affairs at Semmelweis University, Budapest, Hungary. Trained as a medical doctor and having had international research experience in single-molecule biophysics, he currently focuses on nanobiotechnology, biomolecular mechanics, cytoskeletal nanobiology, protein folding and misfolding. He supervises the Nanoscience Network at Semmelweis University and runs a Nanobiotechnology and In Vivo Imaging Center that houses state-of-the-art instrumentation that allows imaging and manipulation from single molecules to small-animal organisms. Author of four books and more than fifty research papers. Member of the European Commission Expert Advisory Group on Nano, Materials and Productions.
Miklos Kellermayer, Unige Murvai, Andrea Horvath, Emoke Laszloffi, Katalin Soos, Botond Penke, Ricardo H.J. Pires
Amyloid is a fibrillar or plaque-like aggregate of incorrectly folded proteins. A number of proteins have been shown to form amyloid fibrils thereby causing severe degenerative diseases such as Alzheimer’s and Parkinson’s diseases or type 2 diabetes. Although the toxicity of the amyloidogenic peptides is expected to preclude their technological applications, the remarkable self-assembling properties of amyloid fibrils have raised the possibility of certain nanotechnological applications. In the present work we have been investigating amyloid ß25-35 (Aß25-35), a toxic fragment of Alzheimer’s beta peptide. Strikingly, Aß25-35 fibrils spontaneously form a trigonally oriented network on mica by epitaxial growth mechanisms. Chemical reactivity can be furnished to the fibrils by introducing a cysteine residue (Aß25-35_N27C) while maintaining oriented assembly properties. Fibril binding is strongly influenced by KCl concentration, due to the competition between K+ ions and the Lys28 side-chain for binding sites on the mica surface. By implementing novel imaging techniques such as in situ atomic force microscopy (AFM) and scanning force kymography, we have explored the kinetics of epitaxial assembly of the mutant fibrils at different peptide and KCl concentrations. We measured the length of Aß25-35_N27C fibrils as a function of time. Increasing free peptide concentration enhanced fibril growth rate, and the critical peptide concentration of fibril assembly was 3.92 µM. Increasing KCl concentration decreased the number of fibrils bound to the mica surface, and above 20 mM KCl fibril formation was completely abolished even at high peptide concentrations. By modulating peptide and KCl concentrations in the optimal ranges established here the complexity of the Aß25-35_N27C network can be finely tuned. The generation of a highly oriented and well-controlled nanoscale array with chemical reactivity paves the way towards constructing a nanotechnological chip for diverse functions ranging from nanoelectronic applications to nanomotor arrays.