Table 3.

Heme iron geometry

	Mb⋯CO*		Mb-CO				Deoxy Mb
	YQR	wt†	YQR	wt‡	wt§	wt¶	YQR	wt‡	wt§	wt¶
Fe-Npplane, Å	0.25	0.19	0.07	0.001	0.05	0.015∥	0.30	0.25	0.32	0.29
Fe-Heme plane, Å	0.31	0.27	0.14	0.05	0.10	—	0.36	0.32	0.4	—
Fe-Nɛ2[His93], Å	2.12	2.25	2.12	2.30	2.27	—	2.23	2.2	2.25	—
Temperature, K	20	20	100	100	277	∼293	120	100	277	∼293
Resolution, Å	1.4	1.5	1.4	1.15	2.0	1.15	1.8	1.15	2.0	1.15

^†Ref. 8. 

^‡Ref. 24. 

^§Ref. 23. 

^¶Ref. 25. 

^∥This value is opposite in direction to all other values: that is, the iron is displaced toward the ligand rather than away from it.