Abstract
Monolayers of dipalmitoyl-phosphatidyl-N-monomethylethanolamine (DPP(Me)E) and dipalmitoyl-phosphatidyl-N,N-dimethylethanolamine (DPP(Me2)E) are studied and compared with dipalmitoyl-phosphatidylethanolamine (DPPE), dimyristoyl-phosphatidylethanolamine (DMPE), and dipalmitoyl-phosphatidylcholine (DPPC) to characterize the influence of the headgroup size. The properties of the condensed phases of DPP(Me2)E and DPP(Me)E are between those of DPPC and DMPE or DPPE. DPPC domains are elongated and the orientation changes continuously, whereas DMPE domains are compact and the orientation jumps at curved lines. The domains of DPP(Me2)E and DPP(Me)E are compact, and not elongated. The orientation changes continuously by 360 degrees around a point in the centered domains, and jumps of the orientation occur only in the case of twinning. Furthermore, the size of the headgroup influences the erection of the aliphatic chains. For DPPC and (DPP(Me2)E), no complete erection of chains occurs, whereas for DPP(Me)E the surface pressure required for the complete erection of chains is much higher than for DPPE. The same tendency is found for the collapse. DPPC monolayers do not collapse. DPP(Me2)E monolayers collapse at a much higher surface pressure than those of DPP(Me)E and DPPE.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Hui S. W., Yu H. Electron diffraction studies of molecular ordering and orientation in phospholipid monolayer domains. Biophys J. 1993 Jan;64(1):150–156. doi: 10.1016/S0006-3495(93)81349-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Langer SA, Sethna JP. Textures in a chiral smectic liquid-crystal film. Phys Rev A Gen Phys. 1986 Dec;34(6):5035–5046. doi: 10.1103/physreva.34.5035. [DOI] [PubMed] [Google Scholar]
- Qiu X, Ruiz-Garcia J, Stine KJ, Knobler CM, Selinger JV. Direct observation of domain structure in condensed monolayer phases. Phys Rev Lett. 1991 Aug 5;67(6):703–706. doi: 10.1103/PhysRevLett.67.703. [DOI] [PubMed] [Google Scholar]