Table 1. Activities of NiSOD mutants expressed in S. lividans TK24 ΔsodN.
| Mutated residue | Mutated to | Activity in cell extracts,* % |
|---|---|---|
| Wild type† | 100 | |
| His-1 | Ala, Cys, Asp, Lys, Asn, Gln, Arg, Trp, and Tyr | ND |
| Asp-3 | Ala | 23 |
| Tyr-9 | Ala | ND |
| Phe | 78 | |
| Lys | ND | |
| Gln | ND | |
| Trp | 45 | |
| Glu-17 | Ala | ND |
| Arg-39 | Ala | ND |
| Arg-47 | Ala | 89 |
ND, not detected (<5%).
*
SOD activity was measured by standard cytochrome c assay. Activity of S. lividans TK24 ΔsodN harboring pIJ702 was subtracted from total SOD activity in cell extract.
†
S. lividans TK24 ΔsodN harboring pIJsodN (pIJ702 vector containing the sodN coding region and the promoter region of sodN gene from S. seoulensis).