4
|
Soares CS, da Silva CO. Conformational study of methylphosphocholine: a prototype for phospholipid headgroups in membranes. J Mol Graph Model 2010; 29:82-92. [PMID: 20627784 DOI: 10.1016/j.jmgm.2010.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Revised: 05/04/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
Abstract
Phospholipid bilayers constitute the largest structural component of cell membranes, in which choline phospholipids are abundant. In this study, through a theoretical sampling on a methylphosphocholine (MePC) potential energy surface, a set of conformers was selected as a prototype for the membrane phospholipid head. We performed a detailed conformational study of such a prototype, both as an isolated moiety and in a solvated system. We used the polarizable continuum model (PCM) to account for solvation effects. We used a quantum-mechanical methodology based on density functional theory (DFT) and the 6-31G(d,p) basis set for the calculations. Through this methodology we were able to obtain a set of conformations that presented a mirror-image pattern, in good agreement with the experimental geometric values for the different phosphocholine derivatives. Potential curves for the main parameters of the dihedral space of MePC were obtained and are provided to guide future force-field parameterizations.
Collapse
Affiliation(s)
- Cinthia S Soares
- Departamento de Química, Universidade Federal Rural do Rio de Janeiro, BR 465, Seropédica, Rio de Janeiro, Brazil
| | | |
Collapse
|
5
|
Kundu S, Chakraborty H, Sarkar M, Datta A. Interaction of Oxicam NSAIDs with lipid monolayer: anomalous dependence on drug concentration. Colloids Surf B Biointerfaces 2008; 70:157-61. [PMID: 19157803 DOI: 10.1016/j.colsurfb.2008.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 12/08/2008] [Indexed: 11/28/2022]
Abstract
Surface pressure (pi) versus specific molecular area (A) isotherms of Langmuir monolayers of dimyristoylphosphatidylcholine (DMPC) lipid on pure water were studied in pristine form and in presence of three non-steroidal anti-inflammatory drugs, meloxicam (MX), piroxicam (PX) and tenoxicam (TX) in the subphase. Data were taken at three drug/lipid (D/L) ratios of 0.026, 0.05, and 0.1. Integration of drug to the lipid monolayer was measured by the increase in A (Delta A) of DMPC monolayer due to the presence of drugs. All three drugs could be integrated in the monolayer resulting in a positive value of Delta A for D/L ratio of 0.026. Above this D/L value, there is an anomalous, monotonic decrease in Delta A for MX and TX resulting, finally, in negative Delta A values. For PX, however, decrease in Delta A values at D/L of 0.05 is partially compensated at D/L of 0.1. We have tentatively explained these observations by invoking two competing forces in the overall drug-lipid interaction. One of these is an 'in-plane' force that tends to integrate the drug molecule to the plane formed by the lipid monolayer and the other is an 'out-of-plane' force that perturbs the drug and the lipid molecules such that the monolayer plane is no longer well defined.
Collapse
Affiliation(s)
- Sarathi Kundu
- Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
| | | | | | | |
Collapse
|
6
|
Krishnamurty S, Stefanov M, Mineva T, Bégu S, Devoisselle JM, Goursot A, Zhu R, Salahub DR. Density Functional Theory-Based Conformational Analysis of a Phospholipid Molecule (Dimyristoyl Phosphatidylcholine). J Phys Chem B 2008; 112:13433-42. [DOI: 10.1021/jp804934d] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. Krishnamurty
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - M. Stefanov
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - T. Mineva
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - S. Bégu
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - J. M. Devoisselle
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - A. Goursot
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - R. Zhu
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - D. R. Salahub
- UMR 5253 CNRS/ENSCM/UM2/UM1, Institut Charles Gerhardt Montpellier, 8 rue de 1ʼ Ecole Normale, 34296 Montpellier Cédex 5, France, Institute of Catalysis, Bulgarian Academy of Sciences, Georgi Bonchev Strasse 11, 1113 Sofia, Bulgaria, and Department of Chemistry and Institute for Biocomplexity and Informatics, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| |
Collapse
|
7
|
Thirumoorthy K, Nandi N, Vollhardt D. Role of dipolar interaction in the mesoscopic domains of phospholipid monolayers: dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylethanolamine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:6991-6. [PMID: 17530786 DOI: 10.1021/la070168z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The role of dipolar interactions in determining the lipid domain shapes at the air-water interface with a change in the chemical structure of the head groups of lipids is theoretically studied. The phospholipids considered are dipalmitoylphosphatidylcholine (D,L-DPPC) and dipalmitoylphosphatidylethanolamine (DPPE). Despite closely similar chemical structures, the domains of the two lipids are strikingly different. The DPPC domains exhibit elongated arms, while the DPPE domains are nearly round-shaped. To compare the dipolar repulsions in the domains of the two phospholipids, different energy-minimized conformers of DPPC and DPPE are studied using the semiempirical quantum chemical method (PM3). It is found that the dipole moment of DPPC is significantly larger than that of DPPE. The in-plane and out-of-plane components of the dipole moments are calculated using grazing incidence X-ray diffraction data at different surface pressure values, as used in the experiment. The result indicates that the magnitude of the dipolar interaction is significantly larger in DPPC than that in DPPE over the surface pressure range considered. The enhanced dipolar repulsion corroborates well with the difference in the domain shapes in the two phospholipid monolayers. The larger dipolar repulsion in DPPC leads to development of elongated domain arms, while relatively less dipolar repulsion allows a closed shape of the condensed-phase DPPE domains.
Collapse
Affiliation(s)
- K Thirumoorthy
- Chemistry Department, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India
| | | | | |
Collapse
|