Model of a sub-main transition in phospholipid bilayers.
A recently discovered submain phase transition in multi-lamellar bilayers of long-chain saturated diacyl phosphatidylcholines (Jørgensen, K. (1995) Biochim. Biophys. Acta 1240, 111-114) is discussed in terms of a theoretical molecular interaction model using computer simulation techniques. The model interprets the transition to be due to a decoupling of the acyl-chain melting from the melting of the pseudo-two-dimensional crystalline lattice of the P beta' phase. A two-stage melting process is predicted by the calculations suggesting that the sub-main transition involves a lattice melting whereas the acyl-chain melting takes place at a higher temperature at the main transition. The calculated heat contents of the two transitions as well as the chain-length dependence compare favorably with experimental data for multi-lamellar phosphatidylcholine lipid bilayers.
Nielsen
M
M
Department of Physics, McGill University, Montreal, Canada.
Miao
L
L
Ipsen
J H
JH
Jørgensen
K
K
Zuckermann
M J
MJ
Mouritsen
O G
OG
D002151:Calorimetry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D013816:Thermodynamics
D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D010743:Phospholipids