Success Rates in Protein Crystallography
- Obtain milligrams of pure, soluble protein.
- About 60% of sequences express well.
- Only one half (prokaryotic) to one quarter (eukaryotic) of these are soluble.
- Obtain high quality crystals.
- Typically hundreds of crystallization
conditions are tested.
- Crystals must be singular, sufficiently large,
and preferably neither needles nor plates.
- Crystals with large numbers of copies in the asymmetric unit
are problematic.
- About half of highly expressed soluble proteins crystallize,
but only about one third of these crystals are suitable.
Overall success rates (Thornton):
-
1-4%
for eukaryotes
- Possibly up to
10-15%
for prokaryotes.
By mid-2005, of 54,000 targets cloned,
nearly 2,000 had been solved
(4%).
Of these, ~1,000(?) nonredundant solved targets represent
6% of the
~16,000-target goal of Structural Genomics.
