FIG. 3.

Amounts of chaperonin 60 measured by Western blotting. (A) MGM100 harboring pBR325 (labelled pBR), pGroES-GroEL (pGro), or pHsp60- Hsp10 (pHsp), grown overnight in LB plus arabinose, were diluted 1:2,000 into LB plus glucose (+G) or arabinose (+A) and sampled after 3 h. MG1655 was grown in LB. All cultures were grown at 37°C. Densitometry of the image shown in panel A and also of others (not shown) on which the extracts were diluted were used to determine protein concentrations. The values for Hsp60 were corrected for the fact (see panel B) that it reacts less well with anti-GroEL. (B) Indicated amounts of purified proteins were used to construct a standard curve for sample measurement. Anti-GroEL detects GroEL with about three times the sensitivity with which it detects Hsp60.