SDS–PAGE of the AtCSN7 core purification steps. Lane 1, material loaded onto Ni2+-chelate column; lane 2, sample of unbound material; lane 3, elution from the Ni2+ -chelate column obtained with 50 mM imidazole; lane 4, protein after overnight TEV protease digestion; lane 5, sample of unbound material from second Ni2+-chelate column; lane 6, sample of material loaded onto Superdex 200 gel-filtration column; lane 7, relevant gel-filtration fractions. MW markers (extreme left) are from top to bottom: 97, 66, 45, 31, 21, 14 kDa. The gel was Coomassie-stained.