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Crystal Structure of the Lipoprotein Localization Factor, LolA
Structural highlights
FunctionLOLA_ECOLI Participates in the translocation of lipoproteins from the inner membrane to the outer membrane. Only forms a complex with a lipoprotein if the residue after the N-terminal Cys is not an aspartate (The Asp acts as a targeting signal to indicate that the lipoprotein should stay in the inner membrane); the inner membrane retention signal functions at the release step.[1] May act as a regulator of the RCS-phosphorelay signal transduction pathway.[2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedLipoproteins having a lipid-modified cysteine at the N-terminus are localized on either the inner or the outer membrane of Escherichia coli depending on the residue at position 2. Five Lol proteins involved in the sorting and membrane localization of lipoprotein are highly conserved in Gram-negative bacteria. We determined the crystal structures of a periplasmic chaperone, LolA, and an outer membrane lipoprotein receptor, LolB. Despite their dissimilar amino acid sequences, the structures of LolA and LolB are strikingly similar to each other. Both have a hydrophobic cavity consisting of an unclosed beta barrel and an alpha-helical lid. The cavity represents a possible binding site for the lipid moiety of lipoproteins. Detailed structural differences between the two proteins provide significant insights into the molecular mechanisms underlying the energy-independent transfer of lipoproteins from LolA to LolB and from LolB to the outer membrane. Furthermore, the structures of both LolA and LolB determined from different crystal forms revealed the distinct structural dynamics regarding the association and dissociation of lipoproteins. The results are discussed in the context of the current model for the lipoprotein transfer from the inner to the outer membrane through a hydrophilic environment. Crystal structures of bacterial lipoprotein localization factors, LolA and LolB.,Takeda K, Miyatake H, Yokota N, Matsuyama S, Tokuda H, Miki K EMBO J. 2003 Jul 1;22(13):3199-209. PMID:12839983[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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