Fig. 1.

Structural organization of psychrophilic PhaCCA. A) Crystal structure of PhaCCA in complex with CTP determined at 1.85 Å resolution. The enzyme monomer presents the characteristic seahorse shape similar to that described by Li et al. [20], with its head, neck, body and tail domains depicted in red, orange, green and blue, respectively. B) Solution structure of PhaCCA including the enzyme core (dark blue) and the flexible 43 residues long N–terminal expression tag (cyan). The theoretical SAXS profile (red line) corresponding to this monomeric model is in good agreement with the experimental data (blue dots), as indicated by the goodness-of-fit (χ²). The error-weighted residual difference plot ΔI/σ = [I_exp(q) – I_model(q)]/σ(q) is given at the bottom. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)