Table 1. Nitrate reductase activity after functional complementation of an E. coli moeB^– strain.

E. coli strain	Expressed proteins	NR, units*
moeB(DE3)	—	ND
moeB(DE3)xpMW15eB†	E. coli MoeB	1.54
moeB(DE3)xpMW15eB-C187A†	E. coli MoeB-C187A	1.12
moeB(DE3)xpAM21‡	MOCS3Δ303-460	ND
moeB(DE3)xpAM17‡	GST-MOCS3	ND
moeB(DE3)xpSL171‡	MOCS3	ND
moeB(DE3)xpSL206§	MOCS2A + MOCS2B + MOCS3	0.43
moeB(DE3)xpSL206-C239A‡	MOCS2A + MOCS2B + MOCS3-C239A	0.08

ND, not detected.

^*Nitrate reductase activity is expressed as μmol of nitrate reduced per min and mg of protein.

^†pMW15eB and variants are described in ref. 10.

^‡Plasmids are described in Materials and Methods.

^§pSL206 is described in ref. 7.