Elizabeth Petro - J. Horn, B. Kraybill, E. Petro, S. Coales, J. Morrow, Y. Hamuro, and A. Kossiakoff.  "The Role of Protein Dynamics in Increasing Binding Affinity for an Engineered Protein-Protein Interaction Established by H/D Exchange Mass Spectrome...

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      J. Horn, B. Kraybill, E. Petro, S. Coales, J. Morrow, Y. Hamuro,   and A. Kossiakoff. "The Role of Protein Dynamics in Increasing   Binding Affinity for an Engineered Protein-Protein Interaction   Established by H/D Exchange Mass Spectrometry." Biochemistry 45:   8488-8498 (2006).


      It is generally accepted that protein and solvation dynamics play   fundamental roles in the mechanisms of protein-protein binding;   however, assessing their contribution meaningfully has not been   straightforward. Here, hydrogen/deuterium exchange mass   spectrometry (H/D-Ex) was employed to assess the role of dynamics   for a high-affinity human growth hormone variant (hGHv) and the   wild-type growth hormone (wt-hGH) each binding to the   extracellular domain of their receptor (hGHbp). Comparative   analysis of the transient fluctuations in the bound and unbound   states revealed that helix-1 of hGHv undergoes significant   transient unfolding in its unbound state, a characteristic that   was not found in wt-hGH or apparent in the temperature factor   data from the X-ray analysis of the unbound hGHv structure. In   addition, upon hormone binding, an overall increase in stability   was observed for the beta-sheet structure of hGHbp which included   sites distant from the binding interface. On the basis of the   stability, binding kinetics, and thermodynamic data presented,   the increase in the binding free energy of hGHv is primarily   generated by factors that appear to increase the energy of the   unbound state relative to the free energy of the bound complex.   This implies that an alternate route to engineer new interactions   aiming to increase protein-protein association energies may be   achieved by introducing certain mutations that destabilize one of   the interacting molecules without destabilizing the resulting   bound complex. Importantly, although the hGHv molecule is less   stable than its wt-hGH counterpart, its resulting active ternary   complex with two copies of hGHbp has comparable stability to the   wt complex.

      Address (URL): http://pubs.acs.org/cgi-bin/abstract.cgi/bichaw/2006/45/i28/abs/bi0604328.html