Question

Why do turns and loops most often occur on the protein surface?

Short answer

The loops and turns often occur on the protein surface because of their hydrophilic residues.

Step-by-step solution

Loops and turns

The loops and turns are the regions of proteins that connect the α helices and β sheets or strands. It allows polypeptide chains to form a more compact structure. They are primarily composed of hydrophilic residues.

Position of loops and turns

The hydrophilic residues of the loops and turns extend toward the surface of the protein, where they are in contact with the aqueous solvent. Also, they shelter the hydrophobic residues of the protein toward the core of the protein.