Figure 3.

Comparison of the RNR ββ′ activity in the Gal-ISC and Gal-CIA mutants grown in iron-free media under GAL-on and GAL-off conditions is shown. A, comparison of the Rnr2 (β) protein levels in the wild-type and the indicated Gal mutants grown in synthetic and iron-free media containing glucose or galactose as described in Fig. 2B. The Western blotting was done three times from independently grown cultures; one representative blot was shown with quantitation. B, measurement of the ββ′ activity in permeabilized spheroplasts of the indicated strains grown in synthetic and iron-free media containing either galactose (GAL-on, solid lines) or glucose (GAL-off, dashed lines) as described in Fig. 2A. Values are given as means ± S.D. (n = 4). C, comparison of the relative specific activities of ββ′ as described in Fig. 2C.