Lipid Binding Dynamics and Structure Function Correlation of a Non-Specific Lipid Transfer Protein

Seeds are the result of sexual reproduction in plants. They are important for the replication of plants during successive seasons. Seeds have vast biological and economic importance to mankind. They are rich in high content of proteins, starch, carbohydrates, oil reserves, fiber, vitamin E and monounsaturated fats. These reserves help in the early stages of growth and development into a plant and also enable to be used as major food sources.

Structural analyses of proteins with naturally bound ligands purified from the native source often provide insights toward their physiological functions. The structure of vicilin from Solanum melongena was determined and two similar ligand binding pockets were found to trap two different ligands, i.e., acetate and pyroglutamate, which were suggested to play roles in the metabolic processes. A homolog of albumin 2 from Lathyrus sativus (LS24) was characterized and the structure was determined. It exists in dimeric form and reveals a hemopexin type fold. The binding of this protein with spermine implicates its role in polyamine biosynthesis. While the spermine binding stabilizes the dimer, the interaction of this protein with heme resulted in monomer formation. Mutually exclusive binding of heme and spermine in different oligomeric states suggested a role for LS-24 in sensing oxidative stress through a ligand-regulated monomer-dimer transition switch. Two surface-bound features for which the electron density could be prominently defined were observed on the surface of the S. melongena nsLTP-I structure and were modeled as lipids.

Legume lectins are the most comprehensively studied group of lectins and have been linked to many pathological and physiological processes. They have been extensively used as immunohistochemistry markers for cancer diagnosis and prognosis and also in cell profiling.