Amino acid sequence, biochemical characterization, and comparative modeling of a nonspecific lipid transfer protein from Amaranthus hypochondriacus.
Plant nonspecific lipid transfer proteins (nsLTPs) are characterized by their ability to bind a broad range of hydrophobic ligands in vitro. Their biological function has not yet been elucidated, but they could play a major role in plant defense to physical and biological stress. An nsLTP was isolated from Amaranthus hypochondriacus seeds and purified by gel filtration and reversed-phase high-performance liquid chromatography techniques. The molecular mass of the protein as determined by mass spectrometry is 9747.29 Da. Data from amino acid sequence, circular dichroism and binding/displacement of a fluorescent lipid revealed that it belongs to the nsLTP1 family. The protein shows the alpha-helical secondary structure typical for plant nsLTPs 1 and shares 40 to 57% sequence identity with nsLTPs 1 from other plant species and 100% identity with an nsLTP1 from Amaranthus caudatus. A model structure of the protein in complex with stearate based on known structures of maize and rice nsLTPs 1 suggests a protein fold complexed with lipids closely related to that of maize nsLTP1.
del Carmen Ramírez-Medeles
María
M
Departamento Sistemas Biológicos, UAM-X, 04960 México, D.F., Mexico.
Aguilar
Manuel B
MB
Miguel
Ricardo N
RN
Bolaños-García
Víctor M
VM
García-Hernández
Enrique
E
Soriano-García
Manuel
M
D027721:Amaranthus / Q000737:chemistry* / Q000145:classification / Q000378:metabolism; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D002352:Carrier Proteins / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002942:Circular Dichroism; D008055:Lipids / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification; D011485:Protein Binding; D017433:Protein Structure, Secondary; D020539:Sequence Analysis, Protein; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D052179:Antigens, Plant; D002352:Carrier Proteins; D008055:Lipids; D010940:Plant Proteins; C511920:lipid transfer proteins, plant; C072087:sterol carrier proteins