Abstract
We have calculated the volume properties (van der Waals volume (V w), molecular volume (V M), and cavity volume (V c)) of various helical peptides and proteins to investigate the relationship between the pressure stability and volume contribution of helical proteins using simple geometric volume calculation method. The calculation value of the cavity volume per amino acid residue (V c/res) of helical proteins shows a good correlation with the adiabatic compressibility of folded proteins. Compared with the experimental results, helical peptides and proteins having a value of V c/res smaller than 20.0 cm3/mol res tend to have large pressure stability, and those having a value of V c/res larger than 25.0 cm3/mol res tend to have small pressure stability. We suggest that the values of V c/res of helical peptides and proteins obtained by simple geometric calculation may be a good candidate for the pressure stability of protein structure.