Crystallization of Lysozyme

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I was doing an experiment on the Crystallization of Lysozyme and wanted to ask, why can't we observe the hexagonal crystals at a very low (around 0.5M) and high (2.0M-3.0M) concentration of NaCl?
Thank you very much

[deleted-718508]

Hi wjdkim826,

To crystallize a protein (or other substances), the protein must (1) be dissolved in solution, then (2) slowly separate out.

Salt ions help with step 1, by providing solubility and stability to proteins. This is why some salt is necessary for crystallization. However, a very-high concentration of salt ions can interfere with protein hydrogen bonds, making proteins less soluble. It takes a fine balance, and the optimal conditions can vary by pH, too.

I hope that helps. Please let us know if you have any more questions.

Best,
Charles