Anomalous Diffusion as Seen through the Lens of Inverted Variable Length Scale FCS

Abstract

Models of Titan predict that there is a subsurface ocean of water and ammonia under a layer of ice. This model could prove important in the search for extraterrestrial life due to its prediction of a potentially habitable environment. In this study, we used molecular dynamics simulations to study proteins in Earth and Titan-like conditions, focusing on the most common secondary structure types: alpha helix and beta sheet. The Earth environment was simulated using a temperature of 300 K, a pressure of 1 bar, and water. The Titan environment was simulated using a temperature of 300 K, a pressure of 1000 bar, and a eutectic mixture of water and ammonia. We analyzed protein compactness, flexibility, and backbone dihedral distributions to identify differences between the two environments. Proteins in the Titan environment were more compact and less flexible, and have small differences in backbone dihedral preferences (e.g., in one instance a stable p-helix formed). These differences could impact affinities between these proteins and other biomolecules.