a, Cryo-EM densities of the LHCII trimer in the supercomplex. Stereo pairs are shown and the view is along the membrane plane. b, Superposition of the cryo-EM structure of an LHCII monomer with the previous crystal structure (PDB code: 1RWT). The protein backbone is shown as ribbon diagrams and the cofactors are displayed as stick models. Green, cryo-EM structure; yellow, crystal structure.