Figure 7: Proposed mechanism for phosphorylation-dependent nucleotide release.

(a) The α and β subunits are shown separated with three domains labelled: the N-terminal domain (‘crown region’), the central nucleotide-binding domain and the C-terminal domain. Phosphosites are shown in yellow and are labelled with the respective residue number. The catalytic binding site of β is shown in red. (b) Schematic of the phosphorylation-dependent conformational changes. The three domains of the α (blue) and β (green) subunits, the phosphorylation sites (yellow) and nucleotide (red) are shown. Cross-links that are decreased following dephosphorylation are shown (dashed lines). Conformational changes in the C-terminal domains of α and β occur upon dephosphorylation, leading to nucleotide release. NBS, nucleotide binding sites.