Table 3. Root mean square deviations I for Ca overlays.

Structure	RMSD (Å)
1XSE_a	1.146
1XSE_b	1.147
3DWF_a	0.982
3DWF_b	0.957
3DWF_c	1.032
3DWF_d	0.962
3G49_a	1.003
3G49_b	1.018
3G49_c	0.983
3G49_d	1.027
1Y5M_a	0.989
1Y5M_b	1.002
1Y5R_a	1.001
1Y5R_b	1.035

For each protein chain (indicated by the lowercase letter) in each crystal structure, the Cα atoms were superimposed onto those of the human 2ILT_a structure and the root mean square deviation was calculated using the Sybyl software [101]. 2ILT_a was used as the reference structure simply because it is the only structure of 11β-HSD1 with only one protein molecule in the crystal structure. The 1XSE, 3DWF and 3G49 structures are of the guinea pig protein and the 1Y5M and 1Y5R structures are of the mouse protein.