Figure 4.

Molecular characterization of the starchless mutant 187G11. A, A 1-bp deletion was identified in the glgA2 gene of 187G11. This point mutation results in a frameshift followed by the appearance of a nonsense codon and the synthesis of a truncated protein (GlgA2*) at the C terminus (Ct). Regions I, II, and III (black boxes), previously characterized to be involved in the binding of ADP-Glc and in catalysis, are conserved in GlgA2*. Nt, N terminus. B, Nevertheless, the YxxxY motif conserved throughout all bacterial GT5 glycosyltransferases has disappeared in GlgA2*.