Figure 1

Ectoine biosynthesis and ectABC gene cluster from Marinococcus halophilus. A: The biosynthetic pathway for ectoine [56, 57] and its dependence on feed-back regulation and/or transcriptional repression of the aspartate kinases in the biosynthetic pathway of the amino acids L-lysine, L-threonine and L-methionine during heterologous expression in E. coli. B: Map of the ectoine biosynthetic genes from M. halophilus as integrated in the plasmids pOSM12 and pOSM2 (only some restriction sites are shown). In case of pOSM2 the natural promoter region upstream of ectA is truncated and replaced by a lac promoter. 1, L-aspartate-kinase I-III; 2, L-aspartate-β-semialdehyde dehydrogenase; 3, L-2,4-diaminobutyric acid transaminase (ectB); 4, L-2,4-diaminobutyric acid Nγ-acetyltransferase (ectA); 5, L-ectoine synthase (ectC).