Figure 2. Mutations in EpsG prevent secretion.

Supernatants of over-night cultures of V. cholerae TRH7000 P_BAD::eps wild-type, P_BAD::ΔepsL containing empty vector or vector encoding wild-type epsL, P_BAD::ΔepsG with empty vector, and vector encoded wild-type epsG or mutants were grown over-night at 37°C. Supernatants were separated from the cells and analyzed for the presence of an extracellular protease using the cleavable fluorogenic substrate N-tert-butoxy-canbonyl-Gln-Ala-Arg-7-amido-4-methyl-coumarin as described in the materials and methods. Each sample was assayed in triplicate and the standard error is indicated.