Predicted binding-sites for FIXa and BiP on the FVIII A domain model. FIXa: two loops, in A2 (S558-Q565) and A3 (E1811-K1818) are shown in pink on the surface of a CPK FVIII image: view perpendicular to the threefold axis with 'top' and 'bottom' of the molecule marked. Also shown is the partly exposed putative BiP binding site (T291-F309) in gold.