Recently Corvera, Laradji, and Zuckermann (unpublished) showed that the multistate lattice model due to Pink, Green, and Chapman [Biochemistry 20, 6692 (1981)] with parameters obtained from fitting to thermodynamic data for saturated phospholipid bilayers does not exhibit a phase transition but could instead be described in terms of short-range fluctuations close to a critical point. We have extended the Pink-Green-Chapman model by including hydrophobic mismatch interactions between the lipid acyl-chain conformational states. We used Monte Carlo techniques to examine the phase behavior of the extended model and found that it exhibits first-order phase transitions above a critical value of the mismatch parameter. The results are discussed in relation to previous theoretical work as well as experimental measurements on lipid bilayers.
Bibliographical noteCopyright (1992) by the American Physical Society.