Escherichia colicells express at least 90 species of lipoprotein. LolB is one of the essential outer membrane lipoproteins, being involved in the last step of lipoprotein sorting. It accepts lipoproteins from a periplasmic molecular chaperone, LolA, and mediates the outer membrane anchoring of lipopro-teins through a largely unknown mechanism. It has been shown previously that a LolB derivative, mLolB, lacking an N-terminal acyl chain, can bind lipoproteins.