Asparagine. Molecular model of the amino acid asparagine. Its chemical formula is C4.H8.N2.O3. Atoms are represented as spheres and are colour- coded: carbon (blue), hydrogen (gold), oxygen (red) and nitrogen (dark blue). Amino acids are the building blocks of proteins. Asparagine is a non-essential amino acid. It can be synthesised by the body and so does not need to come from the diet. Asparagine plays an important role in the folding of protein molecules into their secondary structures (alpha helices and beta sheets). Some proteins (such as haemoglobin, the oxygen- carrying pigment in human blood) cannot function without being folded into the correct shape.