Elucidating Conformational Dynamics and Thermostability of Designed Aromatic Clusters Using Protein Cages.

Abstract

Aromatic residues form clusters in proteins and play essential roles in biological systems. However, the stabilization mechanism and dynamic behavior of aromatic clusters remain unclear. Here, we describe designed aromatic interactions confined within a protein cage to reveal how aromatic clusters affect protein stability. The crystal structures and calorimetric measurements indicate that the formation of inter-subunit phenylalanine clusters enhance the interactions of inter-helices and increase the melting temperature. Theoretical calculations suggest that this is caused by the transformation of the T-shaped geometry into π-π stacking at high temperatures, and the hydration entropic gain. Thus, the isolated nano-environment in a protein cage allows reconstruction and detailed analysis of multiple clustering residues for elucidating the mechanisms of various biomolecular interactions in nature which can be applied to design of bionanomaterials.