Suppose you have engineered a plasmid vector in order to produce a functional animal protein in e. coli. but the product you collect, while it has the correct amino acid sequence, is in fact nonfunctional. what might you try that would have a greater chance of success?

Although E. coli may have translated it correctly, it might not have the same enzymatic modification process present in the original organism where the genetic sequence was taken from. It might be worth trying this enzymatic modification, also called post-translational modification - it is done in order to make some changes to the produced protein (such as introducing a phosphate group) making it functional.