Biomolecule consisting of chains of amino acid residues
This page is about a class of molecules. For protein as a nutrient, see
Protein (nutrient).
File:Myoglobin.pngA representation of the 3D structure of the protein myoglobin showing turquoise α-helices. This protein was the first to have its structure solved by X-ray crystallography. Toward the right-center among the coils, a prosthetic group called a heme group (shown in gray) with a bound oxygen molecule (red).