Question

True or false? All proteins must fold in the four structural levels to be functional

in simple terms can you explain why?

Answer 1

False. Quaternary structure connects different subunits of a protein together by hydrogen bonds.It is not found in all proteins. Hemoglobin which has four subunits has quaternary structure but myoglobin which has only one subunit thus don't have a quaternary structure. We will find abundance of these singular proteins in the human body , they can have primary, secondary and tertiary structure but not quaternary structure.

Single subunit proteins like myoglobin are active under their teritiary folding stage. It binds to oxygen with its single active site. Multisubunit proteins like hemoglobin has more active sites and thus do a higher level binding job than single subunit proteins. Proteins that have quaternary structure thus have more important job to do compared to single subunit proteins which is active in its teritiary folding.