You said you tried macroseeding, but what about microseeding? It works
quite well in many cases. Just don't forget that you should find a zone
were nucleation does not happen before you seed. Take a look at this paper:
Bergfors, T. (2003) Seeds to Crystals, J. Struct. Biol., 142, 66-76.
There is also other methods to separate nucleation and growth. Take a
look at
Saridakis, E., and Chayen, N.E. (2000) Improving protein crystal quality
by decoupling nucleation and growth in vapor diffusion, Protein Sci., 9,
755-757
If you have access to a DLS equipment you may try
Saridakis, E., Dierks, K., Moreno, A., Dieckmann, W.M., and Chayen, N.E.
(2002) Separating nucleation and growth in protein crystallization using
dynamic light scattering, Acta Cryst. Sect. D, 58, 1597-1600.
HTH,
Mario Sanches
Jobichen Chacko wrote:
Hai All,
Sorry for the non Ccp4 question.
I got very small crystals for a protein and I am trying to optimize
the condition to improve the size of the crystal and reduce the number
of nucleation.
The crystals are coming from five to six conditions , all have PEG
3350 in common.
Apart from PEG, the condition has Lithium sulphate and Bis Tris in one
condition and Ammonium suphate and HEPES in another condition, while
the third condition is Sodium malonate, Bis Tris and PEG. I am
getting thousands of small crystals with some precipitation.
I tried macroseeding and additive screen, but the crystals are not
growing.
Any suggestions are more than welcome.
Thank you.
Jobi
--
Mario Sanches
Laboratório Nacional de Luz Síncrotron
Cristalografia e Espectroscopia de Biomoléculas
Tel: +55 19 3512 1109
