Alignment of the steroid-binding domain of MR, GR and CR. Clustal X was used to align the MR, GR and CR sequences. AF2 site is underlined.Pro-637 and Gln-642 in human GR are important in recognition of cortisol [11,15]. Pro-637 and Gln-642 in human GR are conserved in all land vertebrate and teleost GRs. Ser-853 and Leu-848 in human MR are conserved in all land vertebrate MRs, lamprey, hagfish and the proposed ancestral CR and also skate GR.