Fateme Sima Sariaslani

Cloning, nucleotide sequence determination and expression of the genes encoding cytochrome P‐450soy (soyC) and ferredoxinsoy (soyB) from Streptomyces griseus

Xenobiotic transformation by Streptomyces griseus (ATCC13273) is catalysed by a cytochrome P‐450, designated cytochrome P‐450soy A DNA segment carrying the structural gene encoding P‐450soy (soyC) was cloned using an oligonucleotide probe constructed from the protein sequence of a tryptic peptide. Following DNA sequencing the deduced amino acid sequence of P‐450soy was compared with that for P‐450cam, revealing conservation of important structural components including the haem pocket. Expression of the cloned soyC gene product was demonstrated in Streptomyces lividans by reduced CO:difference spectral analysis and Western blotting. Downstream of soyC, a gene encoding a putative [3Fe‐4S] ferredoxin (soyB), named ferredoxinsoy, was identified.