Generic and Specific Roles of Saccharides at Cell and Bacteria Surfaces: Revealed by Specular and Off-Specular X-Ray and Neutron Scattering (Springer Theses)

Systematic investigations of the structure, mechanics, and dynamics of biological surfaces help us understand more about biological processes taking place at cell and bacteria surfaces. Presented here is a study of the role membrane-bound saccharides play in the modulation of interactions between cells/bacteria and their environments. In this thesis, membrane structures were probed perpendicular and parallel to the surface, and sophisticated planar models of biomembranes composed of glycolipids of various structural complexities were designed. Furthermore, specular and off-specular X-ray and neutron scattering experiments were carried out. This research has led to the development of several new methods for extracting information on the structure and mechanics of saccharide-rendered biomembranes from the measured scattering signals. In fact, more is now known about the influence of the saccharide structure. These results demonstrate that the study of planar model systems with X-ray and neutron scattering techniques can provide comprehensive insight into the structure and mechanics of complex biological surfaces. Generic and Specific Roles of Saccharides at Cell and Bacteria Surfaces: Revealed by Specular and Off-Specular X-Ray and Neutron Scattering (Springer Theses)......Page 1 Front-matter......Page 2 Generic and Specific Roles of Saccharides at Cell and Bacteria Surfaces......Page 5 Copyright......Page 6 Supervisor’s Foreword......Page 10 Acknowledgments......Page 12 Contents......Page 14 1 Introduction......Page 17 References......Page 21 2.1.1.1 Membrane Formation by Lipid Self-Assembling......Page 25 2.1.1.2 Phase Behavior of Lipid Membranes......Page 27 2.1.2 Inter-Membrane Interactions......Page 28 2.1.2.2 Van der Waals Interaction......Page 29 2.1.2.4 Undulation Repulsion......Page 30 2.1.2.6 The Disjoining Pressure......Page 31 2.1.3.1 The Discrete Smectic Hamiltonian......Page 32 2.1.3.2 Height--Height Correlation Functions......Page 34 2.1.4.1 Langmuir Lipid Monolayers......Page 35 2.1.4.3 Solid-Supported Lipid Bilayers......Page 37 2.1.4.4 Solid-Supported Membrane Multilayers......Page 38 2.2.1 Basic Principles......Page 39 2.2.1.2 Scattering from Oriented Planar Samples......Page 40 2.2.2.1 Specular Reflectivity from a Single Ideal Interface......Page 42 2.2.2.2 Interfacial Roughness......Page 44 2.2.2.3 Stratified Interfaces......Page 45 2.2.3 Off-Specular (Diffuse) Scattering......Page 46 2.2.3.1 Scattering from a Single, Topologically Rough Interface......Page 47 2.2.3.2 Scattering from Stratified Interfaces with Correlated Topological Roughness......Page 50 References......Page 52 3.1.1.2 Gentiobiose lipid and Lac1 lipid......Page 55 3.1.1.3 LeX lipid......Page 56 3.1.2 Lipopolysaccharides......Page 57 3.1.3 Chemicals and Buffers......Page 58 3.2.1.2 Lipid A and Rough Mutant LPS......Page 59 3.2.2 Preparation of Solid-Supported Membrane Multilayers......Page 60 3.2.4 Preparation of Solid-Supported PAOLPS Monolayers......Page 61 3.3.1.2 GIXOS Experiments at the Air/Water Interface......Page 62 3.3.1.3 X-Ray Fluorescence Experiments......Page 63 3.3.2 Neutron Scattering......Page 64 3.3.3.1 Humidity Chamber for Neutron Scattering under Vapor Conditions......Page 66 3.3.3.2 Liquid Cell for Neutron Scattering under Bulk Water Conditions......Page 67 References......Page 68 4.1.1 Membrane Displacement Correlation Functions......Page 71 4.1.2 Calculation of Specular and Off-Specular Scattering Signals......Page 73 4.1.2.2 Multiple Scattering......Page 78 4.2...Electrostatic Interactions between Charged Lipid Membranes......Page 80 4.2.1 A Single Charged Surface in an Electrolyte......Page 81 4.2.2 Two Charged Surfaces in an Electrolyte......Page 82 4.2.3 The Weak-Overlap Approximation......Page 84 4.3...Interpretation of X-Ray Fluorescence Signals......Page 85 4.3.1 Calculation of Illumination Profiles......Page 86 4.3.2 Calculation of X-Ray Fluorescence Intensities......Page 89 4.3.2.1 Absorption and Buffer-Normalized Fluorescence Intensities......Page 91 References......Page 93 5.1...Influence of Molecular Structure: Cylindrical and Bent Saccharides......Page 95 5.1.1 Phase Transitions of Glycolipid Membranes......Page 96 5.1.2 Modulation of Inter-Membrane Interactions via Saccharide Conformation......Page 98 5.1.3 Influence of Saccharide Conformation on Membrane Mechanics......Page 99 5.1.3.1 Glycolipid Multilayers under Bulk Water......Page 102 5.1.4 Summary of Sect. 5.1......Page 103 5.2...Role of Specific Saccharide--Saccharide Interactions in Membrane--Membrane Contacts......Page 104 5.2.1 Influence of LewisX Trisaccharides on Inter-Membrane Interactions......Page 105 5.2.2.1 Interactions of the Matrix (DPPC) Membranes......Page 106 5.2.2.2 Modification of Matrix Membrane Interactions with Calcium Ions......Page 108 5.2.2.3 Cross-Linking the Membranes: Forces and Energies......Page 110 5.2.3 Influence of LewisX on the Mechanics of Membrane Multilayers......Page 111 5.2.4 Summary of Sect. 5.2......Page 113 References......Page 114 6.1...Influence of Lipopolysaccharide Structure and Divalent Cations on the Mechanics of LPS Multilayers......Page 117 6.1.1 Influence on Inter-Membrane Interactions......Page 118 6.1.2 Influence on Mechanical Properties......Page 120 6.2...Influence of Divalent Cations on the Conformation of Wild-Type Lipopolysaccharides......Page 123 6.2.1 Effect of Divalent Cations: Electron Density Profile of LPS Monolayers......Page 124 6.2.2 Modeling of LPS Saccharide Conformation by Coarse-Grained Monte Carlo Simulations......Page 126 6.2.3 Summary of Sect. 6.2......Page 128 6.3.1 Influence of Divalent Cations on Molecular Interactions in Langmuir Monolayers of LPS Re......Page 129 6.3.2 Influence of Divalent Cations on Electron Density Profiles of LPS Re Monolayers......Page 130 6.3.3 Ion Concentration Profiles at LPS Re Monolayers......Page 132 6.3.4 Modeling of Ion Concentration Profiles at LPS Re Monolayers by Coarse-Grained Monte Carlo Simulations......Page 136 6.3.5 Summary of Sect. 6.3......Page 137 References......Page 138 7 Conclusions......Page 141 8 Outlook......Page 143