Cloning, sequencing and expression of the tetraheme cytochrome c_3 from Desulfovibrio gigas

摘要

The gene encoding the tetraheme cytochrome c_3 from Desulfovibrio gigas was cloned and sequenced from a 2.7-kb EcoRI-PstI insert of D. gigas DNA. The derived amino acid sequence showed that the D. gigas cytochrome C_3 is synthesized as a precursor protein with an N-terminal signal peptide sequence of 25 residues and allowed the correction of the previous reported amino acid sequence (Matias et al. protein Science 5 (1996) 1342-1354). Expression in D. vulgaris (Hildenborough) was possible by conjugal transfer of a recombinant broad-host-range vector pSUP104 containing a SmaI fragment of the D. gigas cytochrome c_3 gene. Biochemical, immunological and spectroscopic analysis of the purified protein showed that the recombinant cytochrome is identical to that isolated from D. gigas.