TABLE 6.

Noncomplementing ApbC variants can be divided into three classes

Growth results are as shown in Table 2.

Variant	Growth	ATP hydrolysisa	Rapid [Fe-S] cluster transfer	Class
ApbC	+	+	+
ApbCK116A	-	+	-	1
ApbCK121A	-	+	-	1
ApbCS122A	-	-	+	2
ApbCS182A	-b	-	+	2
ApbCC283A	-	+	+	3
ApbCC286A	-	+	+	3

^aBiochemical results are shown in Tables 3 and 5.

^bThe ApbC_S182A variant could synthesize thiamine but could not utilize tricarballylate.