2D projection of the chloramphenicol acetyltransferase protein 3D structure. View is from above towards the β-barrel. α-helices are represented as circles, β-strands as triangles. Upward and downward facing triangles represent β-strands directed upwards and downwards, respectively. Regions containing RCRRs are colour coded: a region that contains the predicted RCRRs (red) and a region that has been predicted and was also experimentally examined (blue).