Protein Machineries Involved in the Attachment of Heme to Cytochrome c: Protein Structures and Molecular Mechanisms
Figure 1
The heme-binding site typically observed in c-type cytochromes, as exemplified by a close-up view of the structure of P. aeruginosa Cyt c551 (Pa-Cytc; PDB 351c). The heme is shown in red, while the atoms of the residues from the heme-binding motif of Pa-Cytc (C12VAC15H) and the distal Met61 are color-coded (C: green; O: red; N: blue; S: yellow). The figure highlights the thioether bonds between the Cys12 (on the right) and the vinyl-2, and between Cys15 (on the left) and the vinyl-4. The iron atom of the heme (in gray) is axially coordinated by the distal methionine residue (Met61; shown above the heme plane) and by the proximal histidine residue (His16; shown below the heme plane).
