Universidade Federal de Santa Catarina, Caixa Postal 476,

ABSTRACT. Chromobacterium violaceum presents a distinctive phe-notypic characteristic, the production of a deep violet pigment named violacein. Although the physiological function of this pigment is not well understood, the sequencing of the genome of this bacterium has given some insight into the mechanisms and control of violacein production. It was found that erythrose-4-phosphate (E4P), a precursor to aromatic amino acid biosynthesis, is produced by the non-oxidative portion of the hexose monophosphate pathway, since it lacks 6-phosphogluconate de-hydrogenase. All genes leading from E4P plus phosphoenolpyruvate to tryptophan are present in the genome. Nevertheless, these genes are not organized in an operon, as in E. coli, indicating that other mechan-isms are involved in expression. The sequencing data also indicated the presence and organization of an operon for violacein biosynthesis. Three of the four gene products of this operon presented similarity with nucleo-tide-dependent monooxygenases and one with a limiting enzyme polyketide synthase. As previously suggested, genes encoding proteins involved in quorum sensing control by N-hexanoyl-homoserine-lactone, an autoinducer signal molecule, are present in the bacterial genome. ti l l ():- (2004) FUNPEC-RP www.funpecrp.com.br R.V. Antônio et al. 86 Genetics and Molecular Research 3 (1): 85-91 (2004) www.funpecrp.com.br These data should help guide strategies to increase violacein biosynthe-sis, a potentially useful molecule