How a β-<scp>d</scp>-Glucoside Side Chain Enhances Binding Affinity to Thrombin of Inhibitors Bearing 2-Chlorothiophene as P1 Moiety: Crystallography, Fragment Deconstruction Study, and Evaluation of Antithrombotic Properties
作者:Benny D. Belviso、Rocco Caliandro、Modesto de Candia、Giorgia Zaetta、Gianfranco Lopopolo、Francesca Incampo、Mario Colucci、Cosimo D. Altomare
DOI:10.1021/jm5010754
日期:2014.10.23
The beta-d-glucose-containing compound 3, bearing 2-chlorothiophene and 1-isopropylpiperidine moieties as binders of the S1 and S4 pockets, respectively, proved to be potent competitive inhibitor of factor Xa (fXa, K-i = 0.090 nM) and thrombin (fIIa, Ki = 100 nM). The potency of 3 increases, over the parent compound 1, against fIIa (110-fold), much more than against fXa (7-fold). Experimental deconstruction of 3 into smaller fragments revealed a binding cooperativity of the P3/P4 and propylene-linked beta-d-glucose fragments, stronger in fIIa (15.5 kJ center dot mol(-1)) than in fXa (2.8 kJ center dot mol(-1)). The crystal structure of human fIIa in complex with 3 revealed a binding mode including a strong H-bond network between the glucose O1', O3', and O5' and two critical residues, namely R221a and K224, belonging to the Na+-binding site which may allosterically perturb the specificity sites. The potential of 3 as antithrombotic agent was supported by its ability to inhibit thrombin generation and to stimulate fibrinolysis at submicromolar concentration.