Comparison of the 3D structure of the region containing Ser-949 and His-950 in human MR with other steroid receptors. Ser-949 in human MR and corresponding serine residues in human PR and AR are close to each other and have the Oγ side chain directed away from the receptor core. Human GR lacks this loop. The side chain of Lys-743 in the GR is displaced from His-950 in the MR. In the AF2 binding-domain, Oε2 on Glu-755 in the GR is displaced 3.4 A from Oε2 on Glu-962 in the MR.