A new study in the journal Cell Host & Microbe brings the beneficial bacterial residents of the gut into the mix. The findings show that commensal gut microbes impact the host-pathogen competition for iron and have implications for therapeutic strategies aimed at preventing pathogens from acquiring essential nutrients. Postdoctoral fellow Yasiru (Randy) Perera, PhD, and Walter Chazin, PhD, Chancellor’s Professor of Medicine and professor of Biochemistry and Chemistry, completed structural biology and biophysical studies to probe the mechanistic underpinnings of this back-and-forth between XusB and the Salmonella iron-binding compound.