36% solvent sounds too low.  Most protein crystals are at ~50%.  On the
other hand, if you assume one molecule, your solvent content jumps to
68% - not unheard of, but somewhat high for 1.7A resolution dataset.

But you have a good MR solution, just try to refine/rebuild and see what
you have in the density.

Is your protein a dimer by any chance?  Then you may have two dimers,
only one is formed by crystal symmetry.  Thus you'd have 1.5 molecules
in asu, which would result in solvent content of ~52% - just right.  If
that is the case, run MR with the monomer.

Cheers,

Ed.

On Thu, 2012-04-19 at 02:26 +0100, Krithika Sundaram wrote:
> Hi all,
>
> I am working on an oxidoreductase and having some trouble during molecular replacement.
>
> The resolution of the crystal is 1.7 A and the space group is I4122 (a = b = 121.086, c =156.93 and alpha = beta = gamma = 90).
>
> The cell content analysis results  predicted two molecules in the asymmetric unit and the solvent content as 36 %. The Matthew's coefficient is 1.94. The Wilson plot also looks fine.
>
> However, after molecular replacement (using Phaser) the result just gives me just a single molecule. ( RFZ = 8.5 TFZ =13.9 PAK = 0 LLG =189 TFZ=18.0 LLG = 642)
>
> Any suggestions how to solve this problem?
>
> Thanks in advance.
>