Biophysical characterization of the domain association between cytosolic A and B domains of the mannitol transporter enzymes II(Mtl) in the presence and absence of a connecting linker.

ABSTRACT: The mannitol transporter enzyme II(Mtl) of the bacterial phosphotransferase system is a multi-domain protein that catalyzes mannitol uptake and phosphorylation. Here we investigated the domain association between cytosolic A and B domains of enzyme II(Mtl) , which are natively connected in Escherichia coli, but separated in Thermoanaerobacter tengcongensis. NMR backbone assignment and residual dipolar couplings indicated that backbone folds were well conserved between the homologous domains. The equilibrium binding of separately expressed domains, however, exhibited ∼28-fold higher affinity compared to the natively linked ones. Phosphorylation of the active site loop significantly contributed to the binding by reducing conformational dynamics at the binding interface, and a few key mutatio

SUBMITTER: Lee KO 

PROVIDER: S-EPMC5029529 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature