Answer:
The two proteins may have exactly the same numbers and types of amino acids but the sequence of the amino acids along their polypeptide chain may be different and that is reason enough for them to have different shapes. Amino acids side groups differ in polarity, charges, shape, and size and will determine how the polypeptide folds at local regions within the protein - based on interactions with other local regions within the same chain - or with another chain of a tertiary protein. This is due to the fact that the interactions between amino acid side groups of a polypeptide influence, for example, the number and positions of hydrogen and disulfide bonds within the protein.
