Methyltransferase involved in ribosomal biogenesis. Specifically catalyzes the N1-methylation of pseudouridine at position 914 (Psi914) in 16S rRNA. Is not able to methylate uridine at this position. pseudouridine(914) in M. jannaschii 16S rRNA + S-adenosyl-L-methionine = H(+) + N(1)-methylpseudouridine(914) in M. jannaschii 16S rRNA + S-adenosyl-L-homocysteine Homodimer. Belongs to the class IV-like SAM-binding methyltransferase superfamily. RNA methyltransferase NEP1 family.