4.2 Protein domains are the fundamental units of tertiary structure

polypeptide chain

A protein structural domain is a _____ ______ or a part of one that forms an independent structural unit, typically with a well-defined hydrophobic core.

function

Domains are often units of _____, and proteins may comprise a single domain or several.

50, 200

Protein domains range in size from ~__ to ~__ amino acid residues and represent a great many, perhaps thousands, of distinct polypeptide chain folds.

structural domains

Gene duplication and genetic recombination have resulted in the combinatorial creation of multifunctional proteins by mixing and matching _________ ______

arrangement

Although the general fold of each of the domains is conserved, the three-dimensional _____ of these domains in different proteins can be quite different