Figure 1: Ground state structures, energetics and kinetic mechanism of AdK variants.
From: Structural basis for catalytically restrictive dynamics of a high-energy enzyme state
(a) Ribbon diagrams of the crystal structures of the open apo forms of the wild type (4AKE, red), P177A (4X8H, blue) and Y171W (4X8M, cyan) AdK variants. The ATPlid and AMPbd subdomains are labelled and the trajectories for domain closure into the catalytic closed conformation are indicated with arrows. (b) Crystal structures of the closed Ap5a-bound forms of the wild type (1AKE), P177A (4X8L) and Y171W (4X8O) AdK variants (colour code as in a). (c) A minimal kinetic mechanism of AdK catalysis indicates the presence of a transient high-energy state (highlighted in red) that is simultaneously open and substrate bound. (d) The side chain of Trp171 in Y171W samples two different conformations (cyan and white) in the Ap5a-bound state (4X8O). The side-chain orientation of Tyr171 for wild type (light red) is shown as reference. Ribbon colours as in a. (e) The global enthalpies of unfolding vary considerably for the apo states (open circles) of the wild type, P177A and Y171W, whereas those of the Ap5a-bound states (closed circles) are more closely clustered. Colour code as in a.
