Comparison of lipid binding and transfer properties of two lipid transfer proteins from plants.
Plant lipid transfer proteins (LTPs) are soluble proteins which are characterized by their in vitro ability to transfer phospholipids between two membranes. We have compared the functional properties of two LTPs purified from maize and wheat seeds knowing that, despite a high degree of sequence identity, the two proteins exhibit structural differences. It was found that wheat LTP had a lower transfer activity than the maize LTP, consistent with a lower kinetics of fatty acid binding. The lower affinity for the fatty acids of the wheat LTP could be explained by a narrowing occurring in the middle part of the binding site, as revealed by comparing the fluorescence spectra of various anthroyloxy-labeled fatty acids associated with the two LTPs. The affinity for some natural fatty acids was studied by competition with fluorescent fatty acids toward binding to the protein. Again, wheat LTP had a lower affinity for those molecules. All together, these observations reveal the complexity of the LTP family in plants, probably reflecting the multiple roles played by these proteins.
Guerbette
F
F
Laboratoire de Physiologie Cellulaire et Moléculaire, UMR CNRS 7632, Université Pierre et Marie Curie, Paris, France.
Grosbois
M
M
Jolliot-Croquin
A
A
Kader
J C
JC
Zachowski
A
A
D052179:Antigens, Plant; D001665:Binding Sites; D001692:Biological Transport; D002352:Carrier Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000378:metabolism; D007850:Lauric Acids / Q000378:metabolism; D050356:Lipid Metabolism; D008958:Models, Molecular; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012639:Seeds / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013229:Stearic Acids / Q000378:metabolism; D014908:Triticum / Q000737:chemistry / Q000378:metabolism*; D003313:Zea mays / Q000737:chemistry / Q000378:metabolism*
D052179:Antigens, Plant; D002352:Carrier Proteins; D005456:Fluorescent Dyes; D007850:Lauric Acids; D010940:Plant Proteins; D013229:Stearic Acids; C511920:lipid transfer proteins, plant; C026653:12-(9-anthroyloxy)stearic acid; C040596:12-(1-pyrene)dodecanoic acid