Schematic representation of Isc/Nif operons from different bacteria. Shown is an area of about 10 kb around the IscU/S or NifU/S genes from C. jejuni, H. pylori, A. vinelandii, and E. coli. Isc/Nif genes are indicated by a dark grey box and other genes that are part of the Isc-operon are indicated by a lighter shade of grey. Genes that are not part of the Isc/Nif operon are of yet a lighter shade. Boxes are drawn proportionally with regards to length of the ORF.