Table 1.

Heme propionate hydrogen bond interactions

Interaction	Distances, Å
	T-Cc (Protein Data Bank ID 2AIU)	hh-Cc (Protein Data Bank ID 1hrc)
Heme O1A-Try-48 OH*	2.60	2.69
Heme O1A-Water A OH*	2.59	2.91
Heme O1A-Water B OH*		3.53† (3.05)
Heme O2A-Trp-59 NE1*	2.91	2.67
Heme O2A-Asn-52 ND2*	2.95	3.31
Heme O2A-Gly-41 N*	2.83	3.18
Heme O1D-Thr-49 N	2.99	2.97
Heme O2D-Thr-49 OG1	2.63	2.69
Heme O2D-Lys-79 N	2.99	2.73
Heme O2D-Thr-78 OG1	3.22	2.98

Value in parentheses is averaged mean for rice, horse, iso-1, and iso-2 Cc. Waters A and B are short for equivalents to Water 125 (Water 313 in T-Cc) and Water 139 in hh-Cc, respectively.

*The interactions around Arg-38.

^†Listed for comparison.