Table 2. Fe–His16 and Fe–Met61 distances in monomeric and dimeric WT PA cyt c ₅₅₁.

	Fe–His16 (Å)	Fe–Met61 (Å)
Monomer a	1.99	2.36
Dimer b	2.03	2.32
	2.07	2.30

^a PDB ID: 351C.

^b There are two independent WT PA cyt c ₅₅₁ molecules in the asymmetric unit of dimeric WT PA cyt c ₅₅₁ crystal.