Adenine Recognition Is a Key Checkpoint in the Energy Release Mechanism of Phage T4 DNA Packaging Motor

作者：Kondabagil Kiran; Draper Bonnie; Rao Venigalla B^*

来源：Journal of Molecular Biology, 2012, 415(2): 329-342.

DOI：10.1016/j.jmb.2011.11.013

• molecular motors
• DNA packaging
• virus assembly
• adenine binding
• ATPase

ATP is the source of energy for numerous biochemical reactions in all organisms. Tailed bacteriophages use ATP to drive powerful packaging machines that translocate viral DNA into a procapsid and compact it to near-crystalline density. Here we report that a complex network of interactions dictates adenine recognition and ATP hydrolysis in the pentameric phage T4 large %26quot;terminase%26quot; (gp17) motor. The network includes residues that form hydrogen bonds at the edges of the adenine ring (Q138 and Q143), base-stacking interactions at the plane of the ring (1127 and R140), and cross-talking bonds between adenine, triphosphate, and Walker A P-loop (Y142, Q143, and R140). These interactions are conserved in other translocases such as type I/type III restriction enzymes and SF1/SF2 helicases. Perturbation of any of these interactions, even the loss of a single hydrogen bond, leads to multiple defects in motor functions. Adenine recognition is therefore a key checkpoint that ensures efficient ATP firing only when the fuel molecule is precisely engaged with the motor. This may be a common feature in the energy release mechanism of ATP-driven molecular machines that carry out numerous biomolecular reactions in biological systems.

• 出版日期2012-1-13