Thermal stability and unfolding pathways of Sso7d and its mutant F31A by molecular dynamics simulation

• 1、College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China

Abstract：The thermo-stability and unfolding behaviors of a small hyperthermophilic protein Sso7d as well as its single-point mutation F31A are studied by molecular dynamics simulation at temperatures of 300 K and 500 K. Simulations at 300 K show that the F31A mutant displays a much larger flexibility than the wild type, which implies that the mutation obviously decreases the protein’s stability. High temperature simulations at 500 K suggest that the unfolding of these two proteins evolves along different pathways. For the wild-type protein, the C-terminal alpha-helix is melted at the early unfolding stage, whereas it is destroyed much later in the unfolding process of the F31A mutant. Thus, the mutant unfolds faster than its parent protein. Besides, it is found that the triple-stranded antiparallel -sheet in the wild-type protein plays an important role in maintaining the stability of the entire structure.

keywords： hyperthermophilic protein Sso7d single-point mutation molecular dynamics simulation protein unfolding

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