Table 1. Bacterial strains and plasmids used in this work.

Strains or plasmids	Relevant characteristicsa	Reference or source
Escherichia coli
DH5 α	F−Φ80lac Z ΔM15 Δ(lac ZYA-arg F) U169 rec A1 end A1 hsd R17(rk−,m${}_{\mathrm{k}}^{+}$) pho A sup E44 thi-1 gyr A96 rel A1 λ−	Gibco BRL, Life Technologies
BL21 Codon plus (DE3) RIL	F−ompThsdS (r${}_{\mathrm{B}}^{-}$ m${}_{\mathrm{B}}^{--}$) dcm+galλ(DE3) end A Hte [argU ileY leuW Camr ]	Novagen
22bA/RIL	BL21 Codon plus (DE3) RIL harboring 22bA, Ampr, Camr	This work
28Aa/RIL	BL21 Codon plus (DE3) RIL harboring 28aA, Kanr, Camr	This work
pEA/RIL	BL21 Codon plus (DE3) RIL harboring pEA, Kanr, Camr	This work
pEAX1/RIL	BL21 Codon plus (DE3) RIL harboring pEAX1, Kanr, Camr	This work
AX1R2/RIL	BL21 Codon plus (DE3) RIL harboring pEAX1 and pER2, Kanr, Ampr, Camr	This work
Plasmids
pET22b	Expression vector, C-terminal 6 ×His-tagged sequences, Ampr	Novagen
pET28a	Expression vector, N-terminal 6 ×His-tagged sequences, Kanr	Novagen
pRSFDuet	Expression vector which contains two multiple cloning sites (MCS), N-terminal 6 ×His-tagged sequences, Kanr	Novagen
pETDuet	Expression vector which contains two multiple cloning sites (MCS), N-terminal 6 ×His-tagged sequences, Ampr	Novagen
22bA	pET22b containing doxA coding region, Ampr	This work
28aA	pET28a containing doxA coding region, Kanr	This work
pEA	pRSFDuet containing doxA coding region, Kanr	This work
pEAX1	pRSFDuet containing doxA and fdx1 coding region, Kanr	This work
pER2	pETDuet containing fdr2 coding region, Ampr	This work

Notes.

^aKan^r, Amp^r and Cam^r indicate resistance to kanamycin, ampicillin and chloramphenicol, respectively.