Gold is one of the densest substances known , with a density of 19.3g/cm. if the good in the crown was mixed with less valuable metal like bronze or copper , how would that affect its density

You are studying a protein that you call protein x. there is an aspartic acid at a key position in protein x which is important in the folding and stabilization of that protein. if this aspartic acid is changed to a different amino acid, which type of amino acid substitutions is most likely to allow the protein to fold normally?