In contrast, globular proteins are spherical and generally soluble in water, performing dynamic functions like enzymatic activity or transport.
Such proteins serve protective and structural roles by forming connective tissue, tendons, bone matrices, and muscle fiber.
Collagen is the most abundant of these proteins which exists in vertebrate connective tissue including tendon, cartilage, and bone.
A fibrous protein occurs as an aggregate due to hydrophobic side chains that protrude from the molecule.
A fibrous protein's peptide sequence often has limited residues with repeats; these can form unusual secondary structures, such as a collagen helix.