How environmental factors affect the structural properties and biofunctions of keratin: a molecular dynamics study

Keratin is the primary component of stratum corneum (SC). Due to the abundant resources and intrinsic biophysical properties, such as skin, hair, horns, wools, hooves and so on, keratin-based biomaterials have been widely studied in the past decades. However, the response of keratin to environmental factors is differently compared with other natural polymers determined by its unique complicated hierarchical structure. Therefore, the study of the keratin influence factors is essential in many research areas especially in design of consumer care products and healthcare research. Water, temperature, and ions effects are key factors which can influence the biophysical and mechanical properties of SC. Furthermore, these factors can influence the binding ability between small ligands and keratin through affecting the secondary structure of the keratin. Herein, we use molecular dynamics (MD) simulations to study how environmental factors influence the structure properties of keratin at atomistic scale. Finally, we select Epigallocatechin-3-gallate (EGCG) as a representative model to study the affinity properties of keratin-ligand under different environmental conditions. This keratin-ligand interaction is determined by combined interaction of hydrogen bonding, hydrophobic interaction, the van der Waals and electrostatics interactions. Our findings will provide atomistic insights to broaden the knowledge of how keratin responds to changes in various types of surrounding environment.