FIGURE 7.

Lhs1p functions as a nucleotide-independent holdase. A, firefly luciferase (0.6 μm) was incubated at 43 °C in the absence (●) or presence of 1.2 μm untreated Lhs1p (○) or 3 μm bovine serum albumin (Δ). Aggregation was followed by the increase in optical density at 320 nm. B, GdnHCl-treated Lhs1p and untreated Lhs1p prevent luciferase aggregation with similar efficiency. Maximal firefly luciferase (0.6 μm) aggregation upon incubation at 43 °C in the absence (●) or presence of increasing concentrations of untreated Lhs1p (○) or GdnHCl-treated Lhs1p (□) are indicated. C, the Lhs1p NBD mutations still allow holdase activity. Maximal firefly luciferase (0.6 μm) aggregation upon incubation at 43 °C in the absence (●) or presence of increasing concentrations of Lhs1p (○), Lhs1p(D26A) (□), or Lhs1p(G28A) (Δ). The mean ± S.D. (error bars) from three experiments is shown.