Figure 2.
The complex of ColD with the hydrated form of PLP. Aldehydes react with water to form hydrates. This type of reaction for PLP is shown in A, along with the numbering used to define the various atoms of the cofactor. Electron density corresponding to the hydrated form of PLP is displayed in B. The map, contoured at 2σ, was calculated with coefficients of the form (Fo − Fc), where Fo was the native structure factor amplitude and Fc was the calculated structure factor amplitude from the model lacking coordinates for the PLP. Those residues situated within ∼3.5 Å of the hydrated PLP in subunit 2 are shown in C. The dashed lines indicate possible hydrogen bonds between atoms positioned within 3.2 Å of each other. Asn 248 is contributed by subunit 1.