SDS induced dissociation of STY3178 oligomer: experimental and molecular dynamics studies

Abstract

STY3178 is a yfdX protein from Salmonella Typhi. yfdX proteins occur ubiquitously in a number of virulent bacteria but their cellular localization is unknown. Our earlier studies have shown that STY3178 is a trimer and can be a periplasmic chaperone protein. In the present study we show the stability of STY3178 in the presence of the bio-mimetic anionic surfactant sodium dodecyl sulphate (SDS). With increasing concentrations of SDS we observe monomeric STY3178 which reversibly forms the trimer upon decreasing the surfactant concentration. Protein tertiary structure is not perturbed in the presence of SDS. We show using molecular dynamics simulation and conformational thermodynamics data that SDS induces stability of the monomer compared to an isolated monomer of STY3178. This supports our experimental observations.