Comparison with CbiT homologous proteins. (a) Sequence alignment of MJ0391 from Methanocaldococcus jannaschii, MT0146/CbiT from Methanobacterium thermoautotrophicum, precorrin-6Y C5, C15 – methyltransferase from Geobacter metallireducens GS-15 (Q39YF0), and the putative precorrin-6Y C5, C15 – methyltransferase from Corynebacterium diphtheriae (Q6NHA4). The secondary structural features from MJ0391 are indicated above the alignments. The colors reflect the similarity (red boxes and white characters for conserved residues; red characters for similarity in a group; blue frames for similarity across groups). The sequence was aligned and rendered by Clustal W  and ESPript , respectively. (b) Superposition of MJ0391 (yellow) on the precorrin-6Y C5, C15 – methyltransferase structures from G. metallireducens (PDB ID: 3E05, blue) and CobLc from R. capsulatus (PDB ID: 3NJR, cyan).