Conformational Dynamics of Phus

Abstract

Iron is essential for pathogen's survival and virulence in the host and it requires specialized mechanisms for uptake and storage. PhuS is a cytoplasmic heme-trafficking protein in the opportunistic Gram-negative pathogen Pseudomonas aeruginosa. Heme binding to PhuS has been thought to occur by an induced-fit mechanism. However, this assumption is recently challenged by the structure of the holo form, which shows no significant difference from the apo form. To resolve the controversy, we performed molecular dynamics simulation of the apo form of PhuS. We found that the apo PhuS samples a conformational space distinct from the holo structure, thus providing new insights into the mechanism of heme trafficking in P. aeruginosa.