The N-terminal domain of serine acetyltransferase has a sequence that is conserved in plants [2] and bacteria [1].

1: L-cysteine biosynthesis in Escherichia coli: nucleotide sequence and expression of the serine acetyltransferase (cysE) gene from the wild-type and a cysteine-excreting mutant. Denk D, Bock A; J Gen Microbiol 1987;133:515-525. PMID:3309158

2: Molecular cloning and characterization of a plant serine acetyltransferase playing a regulatory role in cysteine biosynthesis from watermelon. Saito K, Yokoyama H, Noji M, Murakoshi I; J Biol Chem 1995;270:16321-16326. PMID:7608200