Dipalmitoylphosphatidylcholine bilayer

O Leary TJ and Levin IW Raman spectroscopic study of the melting behavior of anhydrous dipalmitoylphosphatidylcholine bilayers. J. Phys. Chem. 1984 88 1790-1796. 

Tieleman, D. P. and Berendsen, H. J. C. (1996). Molecular dynamics simulations of a fully hydrated dipalmitoylphosphatidylcholine bilayer with different macroscopic boundary conditions and parameters, J. Chem. Phys., 105, 4871 —4880. 

Tu, K., Tobias, D. J. and Klein M. L. (1995). Constant pressure and temperature molecular dynamics simulation of a fully hydrated liquid crystal phase dipalmitoylphosphatidylcholine bilayer, Biophys. J., 69, 2558-2562. 

Xiang, T. X. and Anderson, B. D. (1998). Influence of chain ordering on the selectivity of dipalmitoylphosphatidylcholine bilayer membranes for permeant size and shape, Biophys. J., 75, 2658-2671. 

Ruocco, M. J. and Shipley, G. G. (1982a). Characterization of the subtransition of hydrated dipalmitoylphosphatidylcholine bilayers X-ray diffraction study. Biochim. Biophys. Acta 684 59. 

K. Tu, D.J. Tobias, J.K, Blasie, and M.L. Klein. Molecular dynamics investigation of the structure of a fully hydrated gel-phase dipalmitoylphosphatidylcholine bilayer. Biophys. J 70 (1996) 595-608. 

The Marcelja mean field is applicable to simulations of lipids by using continuous torsion angles. A Brownian dynamics simulation (see Brownian Dynamics) was performed for a simple lipid chain to model a dipalmitoylphosphatidylcholine bilayer. The 44 million-step calculation in this continuous Marcelja model simulation was equivalent to approximately 0.66 ps. The internal dynamics of the hydrocarbon chain were very similar to those of a neat alkane. The magnitude and frequency dependence of the NMR data were explained as fast axial rotation superimposed with slow noncollective diffusive director fluctuations (wobble). 

Pandit SA, Bostick D, Berkowitz ML. (2003) Molecular dynamics simulation of a dipalmitoylphosphatidylcholine bilayer with NaCl. Biophys J 84 3743-3750. Bockmarm RA, Hac A, Heimburg T, Grubrniiller H. (2003) Effect of sodium chloride on a lipid bilayer. Biophys J85 1647-1655. 

The identity of the moiety (other than glycerol) esterified to the phosphoric group determines the specific phosphoHpid compound. The three most common phosphoHpids in commercial oils are phosphatidylcholine or lecithin [8002-45-5] (3a), phosphatidylethanolamine or cephalin [4537-76-2] (3b), and phosphatidjlinositol [28154-49-7] (3c). These materials are important constituents of plant and animal membranes. The phosphoHpid content of oils varies widely. Laurie oils, such as coconut and palm kernel, contain a few hundredths of a percent. Most oils contain 0.1 to 0.5%. Com and cottonseed oils contain almost 1% whereas soybean oil can vary from 1 to 3% phosphoHpid. Some phosphoHpids, such as dipaLmitoylphosphatidylcholine (R = R = palmitic R" = choline), form bilayer stmetures known as vesicles or Hposomes. The bdayer stmeture can microencapsulate solutes and transport them through systems where they would normally be degraded. This property allows their use in dmg deHvery systems (qv) (8). 

The rate of transport across bilayer membranes reconstituted from dipalmitoylphosphatidylcholine (DPPC) andnigericin is approximately the same as that observed across membranes reconstituted from DPPC and cecropin a at 35 C. Would you expect the transport rates across these two membranes also to be similar at 50 C Explain. 

Berger, O., Edholm, O. and Jahnig F. (1997). Molecular dynamics simulations of a fluid bilayer of dipalmitoylphosphatidylcholine at full hydration, constant pressure and constant temperature, Biophys. J., 72, 2002-2013. 

In the authors laboratory we have studied the fluorescence depolarization of IR-140 in lipid bilayer membranes of L-a-dipalmitoylphosphatidylcholine (DPPC) and observed similar differences between the gel and liquid crystalline phases as has been widely reported for UV/visible probes such as l,6-diphenyl-l,3,5-hexatriene (DPH) in this same medium. Figure 12.4 shows some of these results. 

This chapter summarizes the first direct determinations of conformational disorder in phospholipid bilayer systems. The model phospholipid chosen is 1,2 dipalmitoylphosphatidylcholine (DPPC), whose physical properties have been widely investigated for two... 

A DSC heating scan of a fully hydrated aqueous dispersion of dipalmitoylphosphatidylcholine (DPPC), which has been annealed at 0°C for 3.5 days, is displayed in Fig. 2. The sample exhibits three endothermic transitions, termed (in order of increasing temperature) the subtransition, pretransition, and main phase transition. The thermodynamic parameters associated with each of these lipid phase transitions are presented in Table 1. The presence of three discrete thermotropic phase transitions indicates that four different phases can exist in aimealed, fully hydrated bilayers of this phospholipid, depending on temperature and thermal history. All of these phases are lamellar or bilayer phases differing only in their degree of organization. 

Brockman, H. Dipole potential of lipid membranes, Chem. Phys. Lipids, 73, 57,1994. Bush, F.S., Adams, R.G., and Levin, I.W. Structural reorganizations in lipid bilayer systems effect of hydration and sterol addition on Raman spectra of dipalmitoylphosphatidylcholine multilayers. Biochemistry, 19, 4429, 1980. 

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