Mycobacterial lipoprotein LprG can bind triacylated phospholipids such as phosphatidylinositol mannoside (PIM) and lipoarabinomannan (LAM). LprG is in an operon reported with an integral membrane transporter. LprG binds to PIM and LAM and transports them to the cell surface of Mycobacterium tuberculosis. [1]
Function
Macromolecule LprG biochemical function is binding and transportation. For binding it interacts selectively and noncovalently with glycerophospholipids and phosphorylated derivatives. As for transportation LprG binds triacylglyceride (TAG) in a large hydrophobic cleft and transfers TAG from donor to acceptor membranes. [1]
Disease
Tuberculosis is an infectious disease that is the second leading cause of death worldwide. Mycobacterium tuberculosis is an intracellular bacterial pathogen in infected macrophages. It contributes to antibiotic resistance and plays a critical role in regulating host response and aid survival of pathogen. LprG determines the components of mycobacterium tuberculosis cell envelope. [1]
Structural highlights
LprG (4ZRA) consists of two chains A and C containing alpha-beta folds. contains 10 anti-parallel ß-sheets with 6 α-helices which defines the central cavity entrance. The is located at the entrance. At the cavity entrance the hydrophilic glyceryl interacts with . There are three acyl chains on the ligand bound within the cavity sn1, sn2, and they form interactions with hydrophobic residue side chains within the cavity. The chain is exposed to the solvent and the other two (sn1 and sn2) buried inside the LprG. The sn3 chain is near two grooves that contain Ile, Leu, Val, and Phe. These grooves could facilitate the binding of TAG with other longer acyl chains.[1]
