Question

Describe how secondary structure motifs are assembled into tertiary and quaternary domains.

Answer 1

Secondary structure motifs which are also known as super secondary structure are made up of different combinations of secondary structure of proteins having about 10- 38 residues. They form structure that lies between simple secondary structure and more complex tertiary structure. As we know that secondary structures could be alpha helix or beta sheets. These structures could helix- turn- helix , two aplha helixes connected by beta turn.These structures can be converted into tertiary and quaternary domain by much more folding and condensing. Motifs are converted into tertiary structure by interaction between the R groups of amino acids that follows a bond formation which is a hydrogen bond. Hydrogen bonds helps in stabilizing the structure and providing structural graphics to protein structures. Now as we move further, motifs become more and more folded and structurally stable.Now polypeptide chains are held more closely by hydrogen bonds as well as disulphide bonds which formed between the polypeptide chains. These bonds connect the folded polypeptide parts together with each other. Somehow these are the folding process that occurs in secondary motifs.