TABLE 2.

Distances between polar atoms in the distal pockets of L86A CerHbO₂, wild-type CerHbO₂, and wild-type aquomet CerHb

The in and out conformation of the Gln-44(E7) side chain are indicated by the superscript “i” and “o” letters.

	wt CerHbO2 (PDB 1kr7)a	Xenon-free L86A CerHbO2 (PDB 2xkg)	Xenon-bound L86A CerHbO2 (PDB 2xkh)	wt aquomet CerHb (PDB 2xki)
Fe—O2 (Å)	1.94	1.97	1.90
Fe—water (Fe3+) (Å)				2.14
Fe-O1-O2 angle (°)	103	110	−105
Tyr-11(B10) OH—O2 (Å)	2.57	2.47	2.46
Tyr-11(B10) OH—water (Fe3+) (Å)				2.87
Gln-44(E7) NE2—O1 (Å)	2.60	2.96
Gln-44(E7) NE2—O2 (Å)			2.65
Gln-44(E7) NE2—water (Fe3+) (Å)				2.72i, 7.13o
Tyr-11(B10) OH—Thr-48(E11) OG1 (Å)	2.59	2.62	2.75	2.68
Tyr-11(B10) OH—Gln-44(E7) NE2 (Å)	3.24	3.33	3.41i, 7.97o	3.59
Gln-44(E7) NE2—Thr-48(E11) OG1 (Å)	3.53	3.34	3.48i, 7.50o	3.34
Gln-44(E7) NE2—solvent water (Å)			2.72o	2.83o
Solvent water—Ala-40(E3) O (Å)			2.59o	2.73o

^a Structure was reported in Pesce et al. (6).