Hi Fred,
If your tetramer show negative cooperativity between the 4
sites for ligand binding, then it is possible to get a tetramer with
(say) only one subunit occupied by ligand, which can introduce
considerable asymmetry if ligand binding gives rise to a hinge type
closure of two domains around the ligand site. An example of this is
glyceraldehyde 3-phosphate dehydrogenase which has been solved with
one, two (and possibly 3) NADs bound per tetramer. I'm afraid you will
need to do a literature search to find the references, but AJ Wonacott
will be one of the authors.
Cheers
Andrew
On 28 Jul 2010, at 19:31, Fred wrote:
> Dear CCP4bb,
> Could someone please, point me to some references about non-
> symmetric tetramers? If I have a tetramer composed by 4 identical
> subunits, it'll always have a P4 point group symmetry?
> Thank in advance,
> Tomb
