Abstract
A dedicated dynamic light scattering (DLS) setup was employed to study the undulations of freely suspended planar lipid bilayers, the so-called black lipid membranes (BLM), over a previously inaccessible spread of frequencies (relaxation times ranging from 10(-2) to 10(-6) s) and wavevectors (250 cm(-1) < q < 38,000 cm(-1)). For a BLM consisting of 1,2-dielaidoyl-sn-3-glycero-phosphocholine (DEPC) doped with two different proportions of the cationic lipid analog dioctadecyl-dimethylammonium bromide (DODAB) we observed an increase of the lateral tension of the membrane with the DODAB concentration. The experimentally determined dispersion behavior of the transverse shear mode was in excellent agreement with the theoretical predictions of a first-order hydrodynamic theory. The symmetric adsorption of the crystalline bacterial cell surface layer (S-layer) proteins from Bacillus coagulans E38-66 to a weakly cationic BLM (1.5 mol % DODAB) causes a drastic reduction of the membrane tension well beyond the previous DODAB-induced tension increase. The likely reason for this behavior is an increase of molecular order along the lipid chains by the protein and/or partial protein penetration into the lipid headgroup region. S-layer protein adsorption to a highly cationic BLM (14 mol % DODAB) shows after 7 h incubation time an even stronger decrease of the membrane tension by a factor of five, but additionally a significant increase of the (previously negligible) surface viscosity, again in excellent agreement with the hydrodynamic theory. Further incubation (24 h) shows a drastic increase of the membrane bending energy by three orders of magnitude as a result of a large-scale, two-dimensional recrystallization of the S-layer proteins at both sides of the BLM. The results demonstrate the potential of the method for the assessment of the different stages of protein adsorption and recrystallization at a membrane surface by measurements of the collective membrane modes and their analysis in terms of a hydrodynamic theory.
Full Text
The Full Text of this article is available as a PDF (118.5 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Büldt G., Gally H. U., Seelig A., Seelig J., Zaccai G. Neutron diffraction studies on selectively deuterated phospholipid bilayers. Nature. 1978 Jan 12;271(5641):182–184. doi: 10.1038/271182a0. [DOI] [PubMed] [Google Scholar]
- Crilly J. F., Earnshaw J. C. Cholesterol-induced effects on the viscoelasticity of monoglyceride bilayers. Biophys J. 1983 Feb;41(2):211–216. doi: 10.1016/S0006-3495(83)84421-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Crilly J. F., Earnshaw J. C. Photon correlation spectroscopy of bilayer lipid membranes. Biophys J. 1983 Feb;41(2):197–210. doi: 10.1016/S0006-3495(83)84420-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grabowski E. F., Cowen J. A. Thermal excitations of a bilipid membrane. Biophys J. 1977 Apr;18(1):23–28. doi: 10.1016/S0006-3495(77)85593-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hirn R., Benz R., Bayerl T. M. Collective membrane motions in the mesoscopic range and their modulation by the binding of a monomolecular protein layer of streptavidin studied by dynamic light scattering. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 1999 May;59(5 Pt B):5987–5994. doi: 10.1103/physreve.59.5987. [DOI] [PubMed] [Google Scholar]
- Macdonald P. M., Leisen J., Marassi F. M. Response of phosphatidylcholine in the gel and liquid-crystalline states to membrane surface charges. Biochemistry. 1991 Apr 9;30(14):3558–3566. doi: 10.1021/bi00228a029. [DOI] [PubMed] [Google Scholar]
- Pum D., Weinhandl M., Hödl C., Sleytr U. B. Large-scale recrystallization of the S-layer of Bacillus coagulans E38-66 at the air/water interface and on lipid films. J Bacteriol. 1993 May;175(9):2762–2766. doi: 10.1128/jb.175.9.2762-2766.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schuster B., Pum D., Braha O., Bayley H., Sleytr U. B. Self-assembled alpha-hemolysin pores in an S-layer-supported lipid bilayer. Biochim Biophys Acta. 1998 Mar 13;1370(2):280–288. doi: 10.1016/s0005-2736(97)00274-5. [DOI] [PubMed] [Google Scholar]
- Schuster B., Pum D., Sleytr U. B. Voltage clamp studies on S-layer-supported tetraether lipid membranes. Biochim Biophys Acta. 1998 Feb 2;1369(1):51–60. doi: 10.1016/s0005-2736(97)00206-x. [DOI] [PubMed] [Google Scholar]
- Sleytr U. B., Sára M., Küpcü Z., Messner P. Structural and chemical characterization of S-layers of selected strains of Bacillus stearothermophilus and Desulfotomaculum nigrificans. Arch Microbiol. 1986 Oct;146(1):19–24. doi: 10.1007/BF00690152. [DOI] [PubMed] [Google Scholar]
- Sára M., Pum D., Sleytr U. B. Permeability and charge-dependent adsorption properties of the S-layer lattice from Bacillus coagulans E38-66. J Bacteriol. 1992 Jun;174(11):3487–3493. doi: 10.1128/jb.174.11.3487-3493.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sára M., Sleytr U. B. Relevance of charged groups for the integrity of the S-layer from Bacillus coagulans E38-66 and for molecular interactions. J Bacteriol. 1993 Apr;175(8):2248–2254. doi: 10.1128/jb.175.8.2248-2254.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weygand M., Wetzer B., Pum D., Sleytr U. B., Cuvillier N., Kjaer K., Howes P. B., Lösche M. Bacterial S-layer protein coupling to lipids: x-ray reflectivity and grazing incidence diffraction studies. Biophys J. 1999 Jan;76(1 Pt 1):458–468. doi: 10.1016/S0006-3495(99)77213-9. [DOI] [PMC free article] [PubMed] [Google Scholar]