|BBa_K3880008||Coding||CDO1(a cysteine dioxygenase)||573|
CDO1 encodes a cysteine dioxygenase with 190 amino acids which has been found in Streptomyces sp. SCUT-3. CDO1 could catalyze cysteine’s oxidation to produce sulfite, which is the key factor for feather degradation. The previous study have demonstrated that overexpression of cdo1 increased bacterial single-cell sulfite production and feather protein conversion efficiency obviously.
Co-overexpression of CDO1 and Sep39 under constitutive promoter ermE increased SCUT-3’s disulfide bond reduction and keratin hydrolysis to achieve higher feather degradation efficiency which exhibited highest total peptide and amino acid yields among SCUT-3, SCUT-Osep39 and SCUT-Ocdo1. However, the co-overexpression of CDO1 and Sep39 under this constitutive promoter ermE yielding fewer cells than SCUT-3 and Sep39 overexpression strain (SCUT-Osep39). To further improve the degradation efficiency without influencing the growth rate, we attempt to modified SCUT-3 through replacing the constitutive promoter with well-characterized promoters.
Sep39 is a major protease involved in SCUT-3’s keratin hydrolysis, and previous work showed that its overexpression could increase SCUT-Osep39’s keratinase activity. To further improve the degradation efficiency without influencing the growth rate, we attempt to balance the expression quantity of CDO1 and Sep39 in SCUT-3 through replacing the constitutive promoter with well-characterized promoters.