Question

Nonpolar amino acid residues are typically found in the interior of globular proteins like chymotrypsin. which chemical force is most directly responsible?

Answer 1

The chemical force most directly responsible in the given case is hydrophobic interactions.  

The hydrophobic interactions illustrate the associations between the hydrophobes, that is, low water-soluble molecules, and water. Hydrophobes are nonpolar molecules and generally exhibit a lengthened chain of carbons, which do not associate with the molecules of water.