FIG 6.

Arrangement of ftsH and folE in Nocardia. GTP cyclohydrolase I, dihydropteroate synthase (DHPS), dihydroneopterin aldolase (DHNA), and hydroxymethyldihydropterin pyrophosphokinase (HPPK) are all involved in the folate biosynthesis pathway. Mutations identified in this region in the TMP-SMX-adapted Nocardia strains (listed in Table 1) are depicted with red starts (mutations within the DHPS gene, which have been discussed in Fig. 3, are shown here to demonstrate the extent of adaptive mutations in this region, making it a mutational hot spot).