Multiple sequence alignment of selected fungal IMPDHs. The region including the amino acid residue at position 415 and part of the flap-region (flap-region being spanned by residues 412 - 467) is presented in the figure. The position 415 is tyrosine in all IMPDHs identified prior to this work . Note that the flap region is very variable, with only residue 415Y and key catalytic residues 441R and 442Y completely conserved in all IMPDHs identified prior to this work . Residues conserved among all nine sequences are highlighted in grey. P. brevicompactum IMPDH-B (encoded by mpaF) is used as a reference while referring to position numbers. P, Penicillium; A, Aspergillus.