SUNY at Albany
June 19-23, 2001
Structures of complexes in the bacterial phosphotransferase pathway (PTS) using new methodology for the rapid determination of macromolecular complexes by NMR
The bacterial phosphoenolpyruvate:sugar phosphotransferase system is a classical example of a signal transduction pathway whereby a phosphorus atom, originating on phosphoenolpyruvate is ultimately transferred to a sugar via a series of phosphoprotein intermediates involving an associative pathway in which successive protein-protein complexes between phosphoryl donor and acceptor molecules are formed. We will present the solution NMR structures of the first two complexes in the glucose branch of the pathway: namely, the 40 kDa complex between the N-terminal domain of enzyme I and the histidine phosphocarrier protein HPr, and betwen HPr and enzyme IIAGlc. Comparsion of these structures reveals how similar binding surfaces can be formed with underlying backbone scaffolds that are structurally dissimilar and illustrates the role of redundancy and sidechain conformational plasticity in protein-protein interactions. These features are likely to be a general characteristic of signal transduction pathways involving transient complex formation between multiple partners.
In addition to the structures we will highlight some novel methods for the rapid determination of macromolecular complexes on the basis of dipolar couplings and intermolecular NOE data using rigid body minimization, constrained/restrained simulated annealing and conjoint rigid body/torsion angle dynamics.References and Footnotes
G. Marius Clore
Laboratory of Chemical Physics, Building 5, NIDDK, National Institutes of Health, Bethesda, MD 20892-0510