Using isoelectric point to determine the pH for initial protein crystallisation trials

Jobie Samuel Kirkwood, David Hargreaves, Simon O'Keefe, Julie C. Wilson

Research output: Contribution to journalArticlepeer-review


The identification of suitable conditions for crystallization
is a rate-limiting step in protein structure determination. The pH
of an experiment is an important parameter and has the potential to
be used in data-mining studies to help reduce the number of crystallisation
trials required. However, the pH is usually recorded as that
of the buffer solution, which can be highly inaccurate.
Results: Here we show that a better estimate of the true pH can be
predicted by considering not only the buffer pH but also any other
chemicals in the crystallisation solution. We use these more accurate
pH values to investigate the disputed relationship between the
pI of a protein and the pH at which it crystallises.
Original languageEnglish
Pages (from-to)1444-1451
Number of pages8
Issue number9
Publication statusPublished - 7 Jan 2015

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