3D models of human ERalpha and ERbeta complexed with 5-androsten-3beta,17beta-diol
Recently, binding of 5-androsten-3beta,17beta-diol (Delta(5)-androstenediol) to human estrogen receptor-beta (ERbeta) was found to repress microglia-mediated inflammation, which is associated with various neurodegenerative diseases, such as multiple sclerosis. In contrast, binding of estradiol to ERbeta resulted in little or no repression of microglia-mediated inflammation. Binding of Delta(5)-androstenediol to ERbeta, as well as to ERalpha, is unexpected because unlike estradiol, Delta(5)-androstenediol has a saturated A ring and a C19 methyl group. To begin to elucidate the interaction of Delta(5)-androstenediol with both ERs, we constructed 3D models of Delta(5)-androstenediol with human ERalpha and ERbeta for comparison with the crystal structures of estradiol in ERalpha and ERbeta. Conformational flexibility in human ERalpha and ERbeta accommodates the C19 methyl on Delta(5)-androstenediol. This conformational flexibility may be relevant for binding of other Delta(5)-steroids with C19 methyl substituents, such as 25-hydroxycholesterol and 27-hydroxycholesterol, to ERs.
Steroids. 2012 Oct;77(12):1192-7. doi: 10.1016/j.steroids.2012.07.014. Epub 2012 Aug 13.
Department of Medicine, 0693 University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0693, USA. mbaker@ucsd.edu
