Base non-specific acid ribonuclease from Irpex lacteus, primary structure and phylogenetic relationships in RNase T2 family enzyme.

Two base non-specific acid RNases (RNase Irp1 and RNase Irp2) were purified from a commercial enzyme, "Driselase" (Irpex lacteus) in a homogenous state on SDS-PAGE by several steps of chromatographic separations. RNAse Irp2 was a simple polypeptide with 235 amino acid residues and RNase Irp1 was a glycopeptide with 248 amino acid residues. The amino acid sequences of both RNases were identified by Edman degradation of the peptides derived from these RNAses. RNase Irp1 was composed of the RNase Irp2 and extra C-terminal 13 residues of peptide. The phylogenetic relation of these RNases with the other fungal RNases already known was discussed. The sequence of RNase Irp2 was very highly homologous (67.5%) with that of RNase Le2 from Lentinus edodes.