Figure 3.

Schematic maps of pIJ303 derivatives used to elucidate the function of spdA2. The spdA homolog spdA2 (black arrow) of plasmid pIJ303 lies downstream of rep. In pIJ303ΔspdA2, spdA2 was replaced (see Materials and Methods) by a linker sequence containing restriction sites (underlined). The NdeI site is coincident with the original spdA2 start codon. The complementing plasmid pIJ303spdA2c contains spdA2 with a C-terminal His-tag encoding sequence (hatched bar), while pIJ303-sps contains a synthetic spdA2-His gene, where the palindromic sequences (upper part, thin arrows) were removed by base substitutions (indicated by red color) that did not alter the amino acid sequence of SpdA2 (lower line).