TABLE 1.

Loss of CyaY activity impacts the activity of the Fe-S cluster enzyme SDH^a

Strain	Relevant genotype	SDH activityb	Relative activityc
DM8000	Wild type	34,840 ± 159	1.00
DM7220	iscS	10,804 ± 102	0.31
DM7644	cyaY	32,645 ± 271	0.93
DM7643	cyaY yggX	8,537 ± 232	0.24
DM7642	apbC cyaY	31,809 ± 113	0.90
DM7641	yggX apbC cyaY	9,679 ± 250	0.27

^aStrains were grown in nutrient broth to an optical density at 650 nm of 0.5. Crude cell-free extracts were generated by sonication as previously described (35). In all cases, loci indicated for relevant genotypes were inactivated by insertion.

^bSDH activity was measured as described previously (34) and is reported as a specific activity (ΔA₆₀₀/min/mg protein [average ± standard deviation]).

^cRelative activity was obtained by dividing the activity of the indicated strain by the activity of the wild-type parent (DM8000).