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. 2019 Aug 14;15(8):e1008086. doi: 10.1371/journal.pgen.1008086

Fig 3. Evolution of the catalytic motifs IV and VI of the fungal Rid-like DNA methyltranferases.

Fig 3

A key catalytic step is the nucleophilic attack of the DNA methyltransferases on the sixth carbon of the target cytosine. This attack is made by the cysteine residue (red arrow) of the conserved PCQ triad (motif IV). This reaction is catalyzed by protonation of the N3 position of the cytosine by the glutamate residue of the conserved ENV triad (motif VI). In the Masc1/Rid-like group of enzymes, the ENV triad is replaced by either the EQT triad (e.g. N. crassa Rid, A. immersus Masc1, P. anserina PaRid, etc.) or the EET triad (e.g. B. cinerea Rid, P. destructans Rid, etc.). Arath: Arabidopsis thaliana, Musmu: Mus musculus, Cenge: Cenococcum geophilum, Maggr: Magnaporthe grisea, Trire: Trichoderma reesei, Fusgr: Fusarium graminearum, Neucr: Neurospora crassa, Pa: Podospora anserina, Geode: Pseudogymnoascus destructans, Botci: Botrytis cinerea, Cocim: Coccidioides immitis. Ascim: Ascobolus immersus, Tubme: Tuber melanosporum, Aspni: Aspergillus nidulans. See above for accession numbers of the corresponding proteins.