We present the search for a new model of beta -factor XIIa, a blood coagula
tion enzyme, with an unknown experimental 3D-structure. We decided to build
not one but three different models using different homologous proteins as
well as different techniques and different modellers. Additional studies, i
ncluding extensive molecular dynamics simulations on the solvated state, al
lowed us to draw several conclusions concerning homology modelling, in gene
ral, and beta -factor XIIa, in particular.