Fig. 7: Proposed shared steps in hsNadE and tbNadE for the glutaminase activation.

Dash and solid curved lines represents disorder and ordered loops, respectively. NP and P indicate a non-productive and a productive glutaminase active site, respectively. Light and dark purple coloring of α-17 indicate the absence or presence of activating interactions with the YRE loop. Similarly, white and color filled stars represent the absence or presence of interactions between α-17 and YRE loop (in red), and YRE and the catalytic triad (in green). Orange, green, dark blue, and light blue spheres represent PPi, the AMP, and NaAD⁺ moiteties of NaAD–AMP, and ammonia. The green filled triangle represents glutamate. The “no access” sign shows the gating mechanism that blocks access to the glutamine tunnel. The addition of Gln is shown in the model after formation of the NaAD–AMP for simplicity but the order of its addition remains unclear.