No, a quaternary structure is not a polypeptide sequence of amino acids. A quaternary structure is the highest level of protein organization and refers to the arrangement of multiple polypeptide chains, also called subunits, into a functional complex. It describes how individual protein subunits interact with each other to form larger, functional entities.

A polypeptide sequence of amino acids, on the other hand, represents the primary structure of a protein and refers to the linear chain of amino acids linked by peptide bonds.