Solvent content

Solvent content can be calculated with the CCP4 program matthews_coef, or with a Web server. Usual values are around 50%, but the range is from about 30% to 85%. Crystals with low solvent content usually diffract better than those with high solvent content.

For pencil-and-paper calculations: The average volume of an amino acid is 140 A**3 ([1]), that of a nucleotide 380 A**3 ([2]).

Protein and nucleic acids have different partial specific volumes (0.74 cm3/g versus 0.50 cm3/g).