Compositions and methods for altering amino acid content or proteins

Abstract

Methods and compositions for altering amino acid composition of a protein of interest are provided, particularly proteins whose three-dimensional structure is unknown. The method comprises creating interacting molecules to the native protein and selecting for engineered proteins which retain the native conformation by antibody binding. In this manner, the levels of essential amino acids in a protein can be increased yet the biological activity of the protein maintained.

1 . A method for altering amino acid composition of a native protein of interest, said method comprising introducing amino acid changes into said protein to create an engineered protein, said engineered protein having the conformation of the native protein wherein said conformation of the engineered protein is confirmed by binding said engineered protein with a set of antibodies capable of binding with the native protein, wherein said antibodies recognize native conformation.  
     
     
         2 . The method of  claim 1 , wherein said native protein is a vegetative storage protein.  
     
     
         3 . The method of  claim 2 , wherein said native protein is soybean VSPβ.  
     
     
         4 . The method of  claim 1 , wherein said amino acid changes alter the amino acid content of the native protein to include substitutions for at least 10% of the amino acids in the native protein.  
     
     
         5 . A method for altering amino acid composition of a native protein of interest, said method comprising introducing amino acid changes into said protein to create an engineered protein having increased level of nutritionally essential amino acids, said engineered protein having the conformation of the native protein wherein said conformation of the engineered protein is confirmed by binding said engineered protein with a set of antibodies capable of binding with the native protein, and wherein said antibodies recognize native conformation.  
     
     
         6 . The method of  claim 5 , wherein said nutritionally essential amino acids are selected from the group consisting of methionine, lysine, and cysteine.  
     
     
         7 . The method of  claim 5 , wherein said nutritionally essential amino acids are increased to represent 5% of the total amino acid content of the protein.  
     
     
         8 . The method of  claim 5 , wherein said nutritionally essential amino acids are increased to represent 10% of the total amino acid content of the protein.  
     
     
         9 . The method of  claim 8 , wherein said nutritionally essential amino acids are selected from the group consisting of methionine, lysine, and cysteine.  
     
     
         10 . The method of  claim 9 , wherein said nutritionally essential amino acid is methionine.