N-methyltransferase; part of the gene cluster that mediates the biosynthesis of 11'-deoxyverticillin A, one of the dimeric epipolythiodioxopiperazines (ETPs) from the verticillin family that act as mycotoxins (PubMed:28376389). 11'-deoxyverticillin A is required for normal conidiation (PubMed:28376389). The nonribosomal peptide synthetase verP is speculated to be responsible for condensation of amino acids to form the carbon skeleton of verticillin, whereas the cluster-specific tailoring enzymes are involved in further modifications leading to the production of 11'-deoxyverticillin A (Probable). Mycotoxin biosynthesis. Expression is regulated by the cluster-specific regulator verZ. Completely abolishes the verticillin production. Belongs to the methyltransferase superfamily. LaeA methyltransferase family.