primary structure

peptide (amide) bond

disulfide bond

phi (ϕ) angle

psi (ψ) angle

Ramachandran plot

secondary structure

α helix

β pleated sheet

β strand

tertiary structure

motif (supersecondary structure)

domain

subunit

quaternary structure

folding funnel

molten globule

intrinsically unstructured protein (IUP)

metamorphic protein

prion