The phosphatidic acid binding site of the arabidopsis trigalactosyldiacylglycerol 4 (TGD4) protein required for lipid import into chloroplasts

Abstract

Background: The phosphatidic acid (PtdOH) binding site of TGD4 is not yet known. Results: Amino acids 1-80 and 110-145 of TGD4 represent two PtdOH interacting sequences and TGD4 forms a homodimer in vitro and in vivo. Conclusion: TGD4 N terminus binds PtdOH while its C terminus interacts with a second TGD4 protein. Significance: This work reveals the structural functional relationship of an essential chloroplast β-barrel lipid transfer protein.© 2013 by The American Society for Biochemistry and Molecular Biology, Inc.