Figure | Overall map for complex I from B. taurus heart mitochondria determined by single-particle cryo-EM.
Architecture of mammalian respiratory complex I. Nature 515, 80-84(2014)
Three distinct features of the complex are revealed by overlaying maps at different density thresholds. The map at the highest threshold (red) reveals the FeS clusters. The map at medium threshold (grey) reveals the overall architecture of the protein and the 78 TMHs in the membrane domain. The detergent–phospholipid belt observed as a dominant feature at low density threshold (translucent blue) represents the density that remains around the membrane domain after cutting out the final model of the protein, and denotes the position of the complex in the membrane. It is ~30 Å thick, and 3–4 Å thinner at the proximal end of the complex (left) than at the distal end (right).