Fig. 3

Genome analysis reveals the ability of C. somerae CS2105-BJ to synthesize vitamin B₁₂ de novo. a Circular genomic map of CS2105-BJ chromosome and six plasmids. From the innermost to outermost circle, Circle 1 represents genome size; Circle 2 (dark purple and bottle green) represents GC skew; Circle 3 (black) shows GC plot; Circles 4 and 7 are color-coded according to the COG classification of the genes located on the forward and reverse strands, respectively. Circles 5 and 6 show the CDSs (dark blue), tRNA genes (dull red), and rRNA regions (purple). b Genomic organization of vitamin B₁₂ biosynthetic genes. The pink arrows represent the genes for Uroporphyrinogen-III synthesis; the purple ones represent genes involved in the corrin ring synthesis; the orange one represents cobalt chelatase gene for insertion of cobalt ions into the corrin ring; the green ones represent genes for the attachment of the aminopropanol arm and assembly of the nucleotide loop in vitamin B₁₂; the blue ones represent the genes encoding ABC transport systems for vitamin B₁₂