PMID: 22357520

Authors:

Amano Y, Yamaguchi T, Ohno K, Niimi T, Orita M, Sakashita H, Takeuchi M

Title:

Structural basis for telmisartan-mediated partial activation of PPAR gamma.

Journal:

Hypertens Res. 2012 Feb 23. doi: 10.1038/hr.2012.17.

Abstract:

Telmisartan, a selective angiotensin II type 1 receptor blocker, has recently been shown to act as a partial agonist for peroxisome proliferator-activated receptor gamma (PPARgamma). To understand how telmisartan partially activates PPARgamma, we determined the ternary complex structure of PPARgamma, telmisartan, and a coactivator peptide from steroid receptor coactivator-1 at a resolution of 2.18 A. Crystallographic analysis revealed that telmisartan exhibits an unexpected binding mode in which the central benzimidazole ring is engaged in a non-canonical-and suboptimal-hydrogen-bonding network around helix 12 (H12). This network differs greatly from that observed when full-agonists bind with PPARgamma and prompt high-coactivator recruitment through H12 stabilized by multiple hydrogen bonds. Binding with telmisartan results in a less stable H12 that in turn leads to attenuated coactivator binding, thus explaining the mechanism of partial activation.Hypertension Research advance online publication, 23 February 2012; doi:10.1038/hr.2012.17.