RNase T2 of Mortierella (phylum Zygomycota)

• The gene encoding the RNase T2 family enzyme was cloned from Mortierella spp.
• The enzymes consist of a catalytic, S/T rich and distinctive C-terminal domain.
• Their catalytic and C-terminal domains are highly conserved among the enzymes.
• The S/T rich domain has no apparent homology among the enzymes.
• The C-terminal region shares similarity with a chitinase from Aspergillus oryzae.

The gene encoding the RNase T2 family enzyme, RNMel36, was cloned from Mortierella elongata (Zygomycota, Mortierellales) by polymerase chain reaction. The deduced protein sequence contains a signal sequence, catalytic domain, S/T rich domain and an extended C-terminal domain. RNase T2 homologs were also cloned from M. alpina, M. parvispora, M. polycephala, and M. verticillata. Their deduced catalytic and the C-terminal domains are highly conserved, unlike that of their S/T rich domains. This is the first report of cloning, heterologous expression, enzyme activity analysis and phylogenetic evaluation of an RNase T2 enzyme from zygomycotan fungi containing a characteristic C-terminal extension.