a. A protein is found to be a tetramer of identical subunits. Name two symmetries possible for

Question:

a. A protein is found to be a tetramer of identical subunits. Name two symmetries possible for such a molecule. What kinds of interactions (isologous or heterologous) would stabilize each?
b. Suppose a tetramer, like hemoglobin, consists of two each of two types of subunits, α and β. What is the highest symmetry now possible?