Figure 7

Ribbon representations. Ribbon diagram corresponding to the prediction of the tertiary structure of K. lactis β-galactosidase (A), A. niger β-galactosidase (B) and hybrid β-galactosidase (C) using the Swiss-Model program. The residues mentioned in Figure 1 have been drawn as spheres of colours (E482 blue, M522 green, Y523 yellow, E551 red). D1–D5 identify the five domains of K. lactis β-galactosidase (A) predicted by alignment in comparison with the sequence of the E. coli β-galactosidase (Figure 1). The fifth domain of the A. niger β-galactosidase is coloured in green (B and C). The white arrow (C) shows the slight opening of the third domain in the hybridβ-galactosidase.