Distinct coordinations of asparagine and glutamine in the catalytic site of E colil-ASP. Snapshots were taken at ∼20 ns of simulation. Q59 typically interacts with the backbone of both asparagine (A; light green) and glutamine (B; orange), but the patterns differ. Asparagine is usually coordinated through its backbone -NH group by the side-chain oxygen of Q59, whereas the backbone carboxyl of glutamine often interacts with the backbone -NH group of Q59, while the side chain of Q59 faces away from the substrate.