Figure 2.

HMP is required for NO consumption and resistance to nitrosative stress. (A) NO metabolism. NADH-dependent consumption of 10 μM NO by extracts (1 mg/ml protein) from untreated Δhmp cells (dotted line, top), SNO-Cys-pretreated Δhmp cells (long-dashed line), untreated wild-type cells (short-dashed line), and SNO-Cys-pretreated wild-type cells (solid line). (B) Cytostatic effect of SNO-Cys treatment on isogenic wild-type (wt) and Δhmp mutant strains (hmp). +/+ and −/−, Cells that had or had not been pretreated with 0.2 mM SNO-Cys for 90 min, respectively, and were then rechallenged with the same dose. −/−, Control (wt or Δhmp mutant) cells that were neither pretreated nor rechallenged with SNO-Cys. In both strains, A₆₀₀ is proportional to cell mass (protein content) at baseline and after treatment. Pretreatments were initiated at A₆₀₀ = 0.2 for 90 min.