FIG. 7.

Cysteine and methionine biosynthesis pathway and its regulation by FhuR in L. lactis. Genes regulated by FhuR or by cysteine starvation are indicated in bold and with thick arrows. Dashed arrows indicate that the reactions could not be fully ascertained from the literature or our experiments. The boxed cysE and the dashed line indicate that CysE is likely subject to feedback control by cysteine. The underlining of O-acetyl-serine emphasizes the fact that this compound might trigger the activity of FhuR. Abbreviations: SAM, S-adenosylmethionine; SAH, S-adenosylhomocysteine; SRH, S-ribosylhomocysteine; AI-2, autoinducer 2.