Kim Ki Won, Wang Zhulun, Busby James, Tsuruda Trace, Chen Michelle, Hale Clarence, Castro Víctor M, Svensson Stefan, Nybo Rebecca, Xiong Fei, Wang Minghan
Department of Metabolic Disorders, Amgen Inc., One Amgen Center Drive, Mail Stop 29-1-A, Thousand Oaks, CA 91320, USA.
FEBS Lett. 2007 Mar 6;581(5):995-9. doi: 10.1016/j.febslet.2007.01.075. Epub 2007 Feb 8.
11beta-Hydroxysteroid dehydrogenase type 1 is a homodimer where the carboxyl terminus of one subunit covers the active site of the dimer partner. Based on the crystal structure with CHAPS, the carboxyl terminal tyrosine 280 (Y280) has been postulated to interact with the substrate/inhibitor at the binding pocket of the dimer partner. However, the co-crystal structure with carbenoxolone argues against this role. To clarify and reconcile these findings, here we report our mutagenesis data and demonstrate that Y280 is not involved in substrate binding but rather plays a selective role in inhibitor binding. The involvement of Y280 in inhibitor binding depends on the inhibitor chemical structure. While Y280 is not involved in the binding of carbenoxolone, it is critical for the binding of glycyrrhetinic acid.
11β-羟基类固醇脱氢酶1型是一种同型二聚体，其中一个亚基的羧基末端覆盖二聚体伙伴的活性位点。基于与CHAPS的晶体结构，推测羧基末端酪氨酸280（Y280）在二聚体伙伴的结合口袋处与底物/抑制剂相互作用。然而，与甘草次酸的共晶体结构与这一作用相悖。为了阐明并协调这些发现，我们在此报告我们的诱变数据，并证明Y280不参与底物结合，而是在抑制剂结合中发挥选择性作用。Y280参与抑制剂结合取决于抑制剂的化学结构。虽然Y280不参与甘草次酸的结合，但它对甘草次酸的结合至关重要。
