Sequence and expression of the rusticyanin structural gene from Thiobacillus ferrooxidans ATCC33020 strain

The periplasmic blue copper protein rusticyanin is thought to play an impor tant role in iron oxidation by Thiobacillus ferrooxidans. We present the se quence of the gene, rus, encoding rusticyanin together with about 1.4 kb of upstream and 0.3 kb of downstream DNA, The, us gene is unique to T. ferroo xidans. Evidence is presented that it is the last gene of an operon and tha t it can be transcribed from its own promoter, In ATCC33020 strain, rusticy anin is synthesized in ferrous iron but also in sulfur growth conditions su ggesting that it could play a role in both energetic metabolisms. The rus g ene transcribed from a vector promoter in Escherichia coli leads to the pro duction of a processed aporusticyanin in the periplasmic space, indicating that its signal sequence is correctly recognized by the secretion machinery and the signal peptidase of E. coli. (C) 1998 Elsevier Science B.V. All ri ghts reserved.