I assume that somehow the two subunits are distinguishable despite their forming a "homodimer." Otherwise I don't know how you would know that it is always the same subunit that contains the water molecule. If they are truly distinguishable, then, the first thing that's come to mind is the possibility that this asymmetric dimer structure is demonstrating a symptom of operating via a half-of-the-sites reactivity mechanism in solution. This would be interesting. I don't know by what mechanism it would be an artifact of the crystallization or structure solution.
Regards, Emily. On Tue, Nov 28, 2017 at 2:04 PM, Denis Rousseau < denis.rouss...@einstein.yu.edu> wrote: > Hi BB members > > I have a homodimeric protein, which contains metal centers. In several > different derivatives I find a water molecule on a metal center in one > subunit which is absent on the other. It is always the same subunit that > contains the water molecule. The resulution is ~2.4 A. Is this an artifact > or a functional difference? If it is truly homodimeric I would expect > differences to be random. The space group is P212121. > > Thanks for the advice. > > Denis Rousseau > ------------------------------ > > -- "Study as if you were going to live forever; live as if you were going to die tomorrow." - Maria Mitchell "I'm not afraid of storms for I'm learning to sail my ship." - Louisa May Alcott
