Stereo views of the β-bulges. The β-bulges that bend the front and back β-sheets are shown. Main chain atoms of parts of β-strands are shown as stick drawings. Bulged residues are numbered and their conformations are given in parentheses (α, α-helix; β, β-strand; I', type I' β-turn; Lα, left-handed α-helix). Hydrogen bond pairs that flank β-bulges are shown in red and the corresponding residues are labelled. Other inter-main chain hydrogen bonds are drawn in grey.