Figure 5.

Analysis of mutants isolated by classical random mutagenesis. (a) Structural context of mutants isolated by classical random mutagenesis. (i) The UreA molecule is shown as helix-succession representation, coloured as in figure 2. The residues affected by the mutations are shown with a space-filling representation. For reference, Y106, A110, N275, Y437 and S446 are shown by stick representation. (ii) Same as (i), but seen from the extracellular side. Stick representations of Y106 and Y437 are included for reference. (b) Epifluorescence microscopy in greyscale inverted mode, showing in vivo subcellular expression of mutant UreA–GFP fusions. Arrows signal perinuclear ER membrane rings. (c) Western blot analysis on total protein extracts of UreA–GFP mutants probed with anti-GFP antibody. See legend of figure 3b for details.