Designing Allosteric Regulators of Thrombin. Monosulfated Benzofuran Dimers Selectively Interact With Arg173 of Exosite 2 to Induce Inhibition

详细信息    查看全文

• 作者：May H. Abdel Aziz ; Preetpal Singh Sidhu ; Aiye Liang ; Ji Yeong Kim ; Philip D. Mosier ; Qibing Zhou ; David H. Farrell ; Umesh R. Desai
• 刊名：Journal of Medicinal Chemistry
• 出版年：2012
• 出版时间：August 9, 2012
• 年：2012
• 卷：55
• 期：15
• 页码：6888-6897
• 全文大小：467K
• 年卷期：v.55,no.15(August 9, 2012)
• ISSN：1520-4804

文摘

Earlier, we reported on the design of sulfated benzofuran dimers (SBDs) as allosteric inhibitors of thrombin (Sidhu et al. J. Med. Chem.201154 5522鈥?531). To identify the site of binding of SBDs, we studied thrombin inhibition in the presence of exosite 1 and 2 ligands. Whereas hirudin peptide and heparin octasaccharide did not affect the IC₅₀ of thrombin inhibition by a high affinity SBD, the presence of full-length heparin reduced inhibition potency by 4-fold. The presence of 纬鈥?fibrinogen peptide, which recognizes Arg93, Arg97, Arg173, Arg175, and other residues, resulted in a loss of affinity that correlated with the ideal Dixon鈥揥ebb competitive profile. Replacement of several arginines and lysines of exosite 2 with alanine did not affect thrombin inhibition potency, except for Arg173, which displayed a 22-fold reduction in IC₅₀. Docking studies suggested a hydrophobic patch around Arg173 as a plausible site of SBD binding to thrombin. The absence of the Arg173-like residue in factor Xa supported the observed selectivity of inhibition by SBDs. Cellular toxicity studies indicated that SBDs are essentially nontoxic to cells at concentrations as high as 250 mg/kg. Overall, the work presents the localization of the SBD binding site, which could lead to allosteric modulators of thrombin that are completely different from all clinically used anticoagulants.