Structure and Activity of the Outer Membrane Protein Ail from Yersinia Pestis

Abstract

Yersinia pestis, the causative agent of plague, is a highly pathogenic organism that spreads rapidly and causes extremely high human mortality. Y. pestis is sensitive to a restricted panel of antibiotics, however, it is classified as a Tier 1 Select Agent due to its extraordinary pathogenicity, the potential weaponization of aerolized bacteria with bio-engineered antibiotic resistance, and the lack of an effective vaccine. The outer membrane protein Ail (attachment invasion locus) is a Y. pestis virulence factor and a prime candidate for therapeutic development due to its two principal activities in mediating bacterial adhesion to host cells and promoting resistance to human complement. Here we present the backbone structure of Ail, determined by NMR spectroscopy in detergent micelles. We also describe activity assays that provide information about the interactions of Ail with its human ligands. Furthermore, we present the results of NMR and activity studies performed with Ail incorporated in phospholipid liposomes and nanodiscs. Overall the data highlight the importance of obtaining structural and functional data in the native-like heterogeneous environment of the lipid bilayer membrane, where the extracellular loops of the protein can be solvated by water and the transmembrane barrel is embedded in the hydrophobic membrane core.This research is supported by a grant from the National Institutes of Health (GM100265). It utilized the NIH-supported NMR Facilities at the Sanford-Burnham Medical Research Institute (CA030199) and at the University of California San Diego (EB002031).