<p>This domain adopts a fold similar to other EGF domains, with a flat major and a twisted minor beta sheet. Disulphide pairing, however, is not of the usual 1-3, 2-4, 5-6 type; rather 1-2, 3-4, 5-6 pairing is found. Its extended major sheet (strands beta-2 and beta-3 and the connecting loop) projects into thrombin's active site groove. This domain is required for interaction of thrombomodulin with thrombin, and subsequent activation of protein-C [<cite idref="PUB00024342"/>]. </p>