Multiple sequence alignment and 3D models of ribonucleases and CSEPs. A: Multiple sequence alignment of ribonuclease T1 from Aspergillus oryzae, a ribonuclease consensus sequence and selected CSEP family consensus sequences. The ribonuclease consensus was derived by aligning ribonucleases from Aspergillus phoenicis (P00653, Penicillium brevicompactum (P07446), Grosmannia clavigera (EFX05096), Phaeosphaeria nodorum (XP_001800520) and Mycosphaerella graminicola (EGP89360). The alignments were manually edited based on MultAlin-alignments (http://multalin.toulouse.inra.fr/multalin/multalin.html). The CSEP families included are primarily those showing most ribonucleases identified by InterProScan or by the structural annotation. The secondary structures (α-helix, β-sheets and loops) of ribonuclease T1 from Aspergillus shown on top are according to Pace et al.. Catalytic active site residues in ribonucleases are indicated in red. Intron position is indicated by a red vertical dashed line; there is one exception, one member of family 56 does not have this intron. Amino acid numberings are the ranges for each family. Upper case letters indicate highly conserved positions, while lower case letters indicate that the positions are present in some of the family members only. Omega (Ω) is used for aromatic amino acids (F, Y and W), and psi (Ψ) is used for V, L and I. Letters in bold indicate that the positions are under purifying selection. Dots indicate non-conserved positions and dashes are gaps. B: 3D models of ribonuclease T1 and three CSEPs and their superposition. Arrows indicate the predicted disulphide bonds between the N- and C-terminal cysteines.