Figure 1 A schematic structural diagram of haem A. The four pyrrole rings are named A, B, C and D. A hydroxylfarnesylethyl group is attached to pyrrole ring A. The tetrahedral C atom C2 of the hydroxylfarnesylethyl group is a chiral atom. The chemical structure around the chiral C atom is given in the box.

© International Union of Crystallography 2005