The outer membrane protein LpxR from Salmonella typhimurium is a lipid A deacylase that catalyses the removal of the 3'-acyloxyacyl moiety from lipid A. This protein folds into a 12-stranded antiparallel beta-barrel with the N- and C- terminal ends pointing towards the periplasm and three extracellular loops consisting of alpha-helical regions at the opposite side of the beta-barrel [1].

1: Active-site architecture and catalytic mechanism of the lipid A deacylase LpxR of Salmonella typhimurium. Rutten L, Mannie JP, Stead CM, Raetz CR, Reynolds CM, Bonvin AM, Tommassen JP, Egmond MR, Trent MS, Gros P; Proc Natl Acad Sci U S A. 2009;106:1960-1964. PMID:19174515