Crystal structure of E. coli lipoprotein diacylglyceryl transferase
Mao, G., Zhao, Y., Kang, X., Li, Z., Zhang, Y., Wang, X., Sun, F., Sankaran, K., Zhang, X.C.(2016) Nat Commun 7: 10198-10198
- PubMed: 26729647 
- DOI: https://doi.org/10.1038/ncomms10198
- Primary Citation of Related Structures:  
5AZB, 5AZC - PubMed Abstract: 
Lipoprotein biogenesis is essential for bacterial survival. Phosphatidylglycerol:prolipoprotein diacylglyceryl transferase (Lgt) is an integral membrane enzyme that catalyses the first reaction of the three-step post-translational lipid modification. Deletion of the lgt gene is lethal to most Gram-negative bacteria. Here we present the crystal structures of Escherichia coli Lgt in complex with phosphatidylglycerol and the inhibitor palmitic acid at 1.9 and 1.6 Å resolution, respectively. The structures reveal the presence of two binding sites and support the previously reported structure-function relationships of Lgt. Complementation results of lgt-knockout cells with different mutant Lgt variants revealed critical residues, including Arg143 and Arg239, that are essential for diacylglyceryl transfer. Using a GFP-based in vitro assay, we correlated the activities of Lgt with structural observations. Together, the structural and biochemical data support a mechanism whereby substrate and product, lipid-modified lipobox-containing peptide, enter and leave the enzyme laterally relative to the lipid bilayer.
Organizational Affiliation: 
National Laboratory of Macromolecules, National Center of Protein Science - Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.