(A) Distribution of conserved sequence motifs in MET12, MET13, H. sapiens MTHFR, and E. coli MTHFR. Motifs 2 and 14 share many conserved amino acid positions but are not completely identical (see File S2 in the supplemental material). Analyses of the sequence between motifs 7 and 9 in H. sapiens MTHFR showed that it did not display a significant level of similarity to motif 8, found in MET12 and MET13 sequences. (B) Sequence logo describing motif number 13, which is unique for the MTHFR belonging to the MET12 group.