Extended Data Fig. 9: Comparison of ISP neck region structure between cytb6f and cytbc1.
From: Molecular basis of plastoquinone reduction in plant cytochrome b6f
a, and b, cryo-EM maps obtained from 3D classification of cytb6f particles frozen during catalysis (ISP head domain was in f- or b-position, respectively). The low intensity of the map of the ISP neck (sequence: GGAGTG) indicates high flexibility of the peptide backbone in this region. c, When DBMIB is bound to cytb6f (PDB ID: 9ES9), the ISP locks in b-position and the ISP neck becomes more rigid and this region is better resolved. The ISP neck in cytbc1 behaves differently: when ISP is in c-position the ISP neck forms α-helix14 (d), when ISP is in the b-position, the helix is stretched13 (e).
