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Free keywords:
(R)-3-amidinophenylalanine; factor Xa; novel active-site binding mode; S1 subregion; synthetic inhibitors; X-ray crystal structure
Abstract:
A putative nonsubstrate like binding mode of (R)-3- amidinophenylalanine derivatives to factor Xa, as derived from modeling experiments based on Xray analysis of their complexes with trypsin, was used to design a new generation of inhibitors. However, the resulting inhibitory potencies were not at all consistent with the working assumption, although with an adamantylureido derivative of (R)-3- amidinophenylalanine phenetyl amide a highly selective nanomolar inhibition of factor Xa was achieved. The Xray analysis of the complex of this ligand with factor Xa revealed an unexpected new binding mode, of which the most important feature is the interaction of the Cterminal aryl moiety with a hydrophobic subregion of the S1 subsite, while the adamantyl group occupies the hydrophobic S3/S4 subsites of the enzyme.
