Figure 1.

The evolution of C45 from humble beginnings. (a) Evolutionary diagram displaying the broad design strokes and functions of the maquettes from a simple featureless 4-helix bundle (1) [35], to the oxygen binding HP7 maquette (2) [35], to the functional de novo enzyme C45 (3) [22^••]. (b) Sequence alignment of three maquettes from the evolutionary diagram of C45. Heme-ligating histidines are highlighted in blue, CXXC from the c-type cytochrome consensus motif (CXXCH) is highlighted in red, and the interhelical loops are displayed in purple.