On Thu, Dec 11, 2008 at 8:09 AM, Santarsiero, Bernard D.
<[log in to unmask]> wrote:
In parallel with the discussion around this off-CCP4-topic, are they any
good examples of the opposite case, where the protein is a monomer in
solution (as evident from light scattering, MW determination through
centrifugation, EPR, etc.) but crystallizes as a dimer or higher multimer?
There are several families of receptor kinases that behave like this, specifically EGFR in humans and some of the Ser/Thr kinases in M. tuberculosis. The kinase domains alone have very low (millimolar) affinity but dimerization in response to an extracellular signal is required for activation. In both cases the activation mechanisms were not understood until the dimeric crystal structures were (accidentally) obtained, and were later confirmed by biochemical experiments:
