Program

P.41 -- Poster, NCTP-41

Date: Wednesday, 3 August 2016

Time: 08h30 - 10h00

Sequence dependent aggregation of peptides and fibril growth

Nguyen Ba Hung (1,2), Le Duy Manh (1), Trinh Xuan Hoang (1)

(1) Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan,Ba Dinh, Ha Noi, Viet Nam (2) Vietnam Military Medical University, 160 Phung Hung, Ha Dong, Ha Noi, Viet Nam

We study the aggregation of peptides in the tube model of proteins with hydrophobic-polar (HP) amino acid sequences and correlated side chain orientations for hydrophobic interaction. Monte Carlo simulations are carried out to calculate equilibrium and dynamic properties of systems of different numbers of peptides and for various sequences of length of 8 amino acids. It is shown that the aggregation propensity as well as the structures of aggregates are strongly dependent on the amino acid sequence and the number of peptides. At a presumable physiological temperature, aggregation is observed not for all but several sequences. Among the sequences studied, only one leads to a fibril-like $\beta$-sheet structure. The fibril growth depends on peptide concentration and is consistent with the nucleation and growth mechanism. The time dependence of the number of fibril-forming peptides is essentially exponential at low temperatures, and it becomes sigmoidal near the aggregation transition temperature. Strikingly, a binary mixing of peptides with fibril prone and non-fibril prone sequences shows conversion of the latter to fibrillar structure.

Presenter: Nguyen Ba Hung