JBScreen PACT++ is a crystallization screen facilitating systematic pH, anion- and cation testing in the presence of polyethylene glycol (PEG) based on the work of Newman et al. .
The 96 unique crystallization conditions combine three mini-screens in one:
1. 24-condition PEG/pH screen
2. 24-condition PEG/cation screen
3. 48-condition PEG/anion screen
This systematic approach aims to alter individual components of the crystallization conditions, i.e. pH, anions and cations, independently from the others in order to obtain more information of the precipitation behaviour of the protein.
When JBScreen PACT++ is used along with JBScreen JCSG++, systematic investigation of the precipitation behaviour of the protein can be combined with a sparse matrix screen in order to enhance the success rate of protein crystallization.
Bulk – 24 or 96 screening solutions in 10 ml aliquots
HTS – 96 screening solutions delivered in a deep-well block, 1.7 ml per well
 Newman et al. (2005) Towards rationalization of crystallization screening for small- to medium-sized academic laboratories: the PACT/JCSG+ strategy. Acta Cryst. D 61:1426.