Genomic organization of the reductive pathway.

<p>(A) Orthologous <i>dha</i> genes (in grey) are represented by block arrows showing their position and orientation (out of scale). Gene arrangement is conserved in the seven organisms shown. <i>Mesorhizobium</i>, <i>Mycobacterium</i> and <i>Hyphomicrobium</i> have fused <i>dhaB1</i> and <i>dhaB2</i> genes. (B) Fusobacterium <i>I</i>. <i>polytropus</i> contains two <i>dha</i> regulons: genes coding for GDHt B12-dependent and its reactivation factor (grey arrows) are found in the plasmid or in the genome; and those coding for B12-independent (red arrows) are present in the genome. (C) Partial sequence alignment of the B12-independent glycerol dehydratase large subunit showing a highly conserved region corresponding to a glycyl radical domain.