Outer Membrane Vesicles of <i>Acinetobacter baumannii</i> DS002 Are Selectively Enriched with TonB-Dependent Transporters and Play a Key Role in Iron Acquisition
Ganeshwari Dhurve, Ashok Kumar Madikonda, Medicharla V. Jagannadham, Dayananda Siddavattam
Abstract
TonB-dependent transporters (TonRs) play a crucial role in transporting nutrients such as iron, nickel, copper, and complex carbohydrates across the energy-deprived outer membrane. Due to their unique structural features, TonRs capture nutrients in an energy-independent manner and transport them across the outer membrane by harvesting energy derived from the inner membrane-localized Ton-complex. In this study, we report the presence of TonRs capable of transporting various nutrients in OMVs and demonstrate their role in capturing and transporting ferric iron complexed with enterobactin into A. baumannii DS002 cells. The OMV-associated TonRs appear to play a critical role in the survival of A. baumannii, listed as a priority pathogen, under nutrient-deprived conditions.