Table 3.

Interspecies ligand RMSD values and Sc indices for ligand-receptor residue contacts of Group A ligands docked into human, mouse, and rat ERα-LBD receptors.

Compound	RMSD (Å)^a				Sc index (%)^b
Compound	Human/Mouse	Human/ Rat	Mouse/Rat		Human/Mouse	Human/ Rat	Mouse/Rat
Parabens
MeP	1.82	1.83		0.08	84.8	84.8	100
EtP	2.51	2.96		1.05	72.7	74.3	93.8
PrP	1.20	1.33		0.47	84.2	89.5	95
BuP	3.22	3.30		0.10	81.0	81.0	100
PeP	0.31	0.21		0.19	100	100	100
HxP	0.18	0.16		0.12	100	100	100
HpP	0.21	0.13		0.13	100	100	100
OcP	0.49	0.47		0.15	100	97.9	97.9
NnP	0.23	0.27		0.23	100	100	100
DecP	3.60	3.57		0.12	90.6	90.6	100
UnDecP	3.45	1.19		3.52	96.0	98.0	93.9
DoDecP	0.66	3.62		3.64	94.1	92.3	96.3
iPrP	0.36	1.74		1.54	97.0	86.5	88.9
iBuP	0.14	0.18		0.09	100	100	100
iPeP	0.46	0.50		0.24	97.7	97.7	100
PhP	1.79	1.72		0.13	95.5	97.7	97.8
BzP	2.09	2.11		0.09	89.4	89.4	100
Parabens metabolites
4OH	0.15	0.27		0.34	96.8	89.7	93.3
2OH	2.09	2.08		1.02	88.4	88.4	100
3OHR	1.79	1.73		0.18	90.0	90.0	100
3OHS	0.15	0.13		0.16	97.7	97.7	100
Established ERα agonists
E2	0.08	0.22		0.18	100	100	100
DES	0.11	0.14		0.05	100	100	100

Symmetry-corrected heavy-atom interspecies ligand RMSD values for Group A ligands docked into mouse and rat ERα-LBD receptors. Overall group RMSD values (median, 95% CI, n = 23) were 0.49 (0.21, 1.82) Å (human-mouse), 1.19 (0.22, 1.83) Å (human-rat), and 0.18 (0.12, 0.34) Å (mouse-rat). By definition, RMSD (human-human) = 0.00 Å.

Sorenson similarity coefficient (Sc) = [2(N_AB)/(N_A + N_B)] x 100, where N_A = number of contacts in receptor A, N_B = number of contacts in receptor B, and N_AB = number of contacts shared by receptors A and B. In this case, contacts are ligand-receptor residue contacts. Sc values (median, 95% CI, n = 23) for all ligands were 96.8 (90.0, 100)% (human-mouse), 97.7 (89.5, 100)% (human-rat), and 100 (97.8, 100)% (mouse-rat). By definition, Sc (human-human) = 100%.