aeruginosa Secretion in Pseudomonas Membrane Is Required for Extracellular Assembly of XcpR in the Cytoplasmic

geneproducts. XcpR, a putative nucleotide-binding protein, is essential for the secretion process across the outermembrane even though the protein contains no hydrophobic sequence that could target or anchor it to thebacterial envelope. For a better understanding of the relationship between XcpR and the other Xcp proteinswhich are located in the envelope, we have studied its subcellular localization. In a wild-type