Table 2. Root mean square deviation values for Ca overlays.

Structure	RMSD (Å)	Structure	RMSD (Å)	Structure	RMSD (Å)
1XU7_a	2.139	2RBE_c	0.341	3D4N_c	2.463
	1.624		0.355		0.404
1XU7_b	1.925	2RBE_d	0.915	3D4N_d	2.452
	0.364		0.505		0.416
1XU7_c	1.944	3BYZ_a	0.543	3D5Q_a	2.051
	0.345		0.452		0.329
1XU7_d	1.928	3BYZ_b	0.528	3D5Q_b	1.906
	0.304		0.443		0.376
1XU9_a	2.227	3BYZ_c	0.366	3D5Q_c	0.974
	1.621		0.328		0.302
1XU9_b	2.519	3BYZ_d	0.877	3D5Q_d	1.940
	0.414		0.440		0.426
1XU9_c	2.524	3BZU_a	0.865	3EY4_a	0.654
	0.439		0.456		0.553
1XU9_d	2.487	3BZU_b	1.436	3EY4_b	0.483
	0.332		0.343		0.484
2BEL_a	1.176	3BZU_c	0.663	3EY4_c	0.383
	0.797		0.269		0.458
2BEL_b	3.045	3BZU_d	0.620	3EY4_d	0.909
	0.815/0.816		0.387		0.509
2BEL_c	4.390	3CH6_a	0.837	3FCO_a	1.646
	0.444		0.223		0.585
2BEL_d	2.997	3CH6_b	3.906	3FCO_b	1.609/1.608
	0.633		0.218		0.462/0.461
2IRW_a	0.820	3CH6_d	3.873	3FRJ_a	1.969
	0.241		0.186		0.566
2IRW_b	0.822	3CH6_e	0.857	3FRJ_b	2.480
	0.237		0.231		0.714
2IRW_c	0.404	3CZR_a	2.490	3H6K_a	0.817
	0.259		0.612		0.441
2IRW_d	0.791	3CZR_b	2.005	3H6K_b	0.740
	0.262		1.003		0.256
2IRW_e	0.387	3D3E_a	1.975	3H6K_c	0.729
	0.279		0.891		0.451
2IRW_f	0.820	3D3E_b	1.975	3H6K_d	0.561
	0.309		0.457		0.360
2IRW_g	0.837	3D3E_c	2.021	3HFG_a	0.673
	0.257		0.743		0.538
2IRW_h	0.831	3D3E_d	2.014	3HFG_b	1.465
	0.250		0.748		0.333
2RBE_a	0.669	3D4N_a	1.936	3HFG_c	0.594
	0.587		0.408		0.414
2RBE_b	0.380	3D4N_b	2.472	3HFG_d	0.561
	0.353		0.304		0.373

For each protein molecule (indicated by the lowercase letter) in each crystal structure of human 11β-HSD1, the Cα atoms were superimposed on those of 2ILT_a and the RMSD 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 chain in the structure. The numbers in normal type are for the whole protein and the numbers in bold are for the residues around the substrate and cofactor binding sites (T40-G47, T64-S67, G91-F98, N119-L126, K138-V142, V168-K187 and L215-M233). Note that for the whole protein 3FCO_b has three Cα atoms with alternate conformations, giving rise to different values for the RMSD. The 2BEL_b, 3CZR_a and 3CZR_b structures have, respectively, two, three and one Cα atoms with alternate conformations, but in these structures the differences, at least to four significant figures, make no difference to the RMSD when superimposed on 2ILT_a. For the binding-site residues, the 2BEL_b structure has different RMSD values for the two conformations. RMSD: Root mean square deviation.