Architecture of the Keap1 Kelch domain. The six individual blades of the highly symmetric β-propeller (grey ribbons) are connected by the interblade A–D loops (red); the B–C loops are coloured orange. The Nrf2-binding site is formed by the interblade A–D loops and the B–C loops. The small β-sheet inserted into the B–C loop of the second blade is coloured blue. All figures were created with PyMOL (Schrödinger).