Optimization of salt concentration in PEG-based crystallization solutions.

ABSTRACT: Although polyethylene glycol (PEG) is the most widely used precipitant in protein crystallization, the concentration of co-existing salt in the solution has not been well discussed. To determine the optimum salt concentration range, several kinds of protein were crystallized in a 30% PEG 4000 solution at various NaCl concentrations with various pH levels. It was found that, if crystallization occurred, the lowest effective salt concentration depended on the pH of the protein solution and the pI of the protein molecule; that is, higher salt concentrations were required for crystal growth if the difference between pH and pI was increasing. The linear relationship between the charge density of the protein and the ionic strength of the crystallization solution was further verified. These resul

SUBMITTER: Yamanaka M 

PROVIDER: S-EPMC3004262 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature