The Enzymes of Biological Membranes

of Volume 1.- 1. Electron Microscopy of Biological Membranes.- I. Introduction.- II. Methods Used for Studying Biological Membranes in the Electron Microscope.- A. Sectioning.- B. Negative Staining.- C. Freeze-Etching and Freeze Fracturing.- D. Split Membrane Technique.- E. Immunoelectron Microscopy.- F. Colloidal Gold Marker.- G. Cryoelectron Microscopy.- H. Image Processing and Three-Dimensional Structure Determination.- References.- 2. Associations of Cytoskeletal Proteins with Plasma Membranes.- I. Introduction.- II. The Components of the Cytoskeleton.- A. Actin.- B. Microtubules.- C. Intermediate Filaments.- D. The Role of ?-Actinin.- III. Cytoskeletal Functions.- IV. The Erythrocyte Membrane Skeleton: A Completely Membrane Associated Cytoskeleton.- A. Composition of the Erythrocyte Membrane Skeleton.- B. Spectrin.- C. Actin.- D. Polypeptides 4.1 and 4.9.- E. Ankyrin.- F. Associations between Spectrin, Actin and Band 4.1.- G. Ultrastructure of the Membrane Skeleton.- V. Cytoskeletal Involvement in Cell-Substratum Associations.- A. Focal Adhesions.- B. The Role of ?-Actinin and Vinculin in Focal Adhesions.- C. Association of Vinculin with F-Actin.- D. Effects of Cell Transformation on Focal Adhesions.- E. The Relationship of Focal Adhesions with the Extracellular Matrix.- F. The Formation of Focal Adhesions.- G. The Function of Focal Adhesions.- VI. Cytoskeletal-Membrane Interactions in Microvilli of the Intestinal Brush Border.- VII. Membrane-Associated Cytoskeletal Elements and the Control of Cell Surface Receptor Dynamics.- A. Capping.- B. Endocytosis.- C. Cell Surface Receptor Topography and Mobility.- VIII. Summary.- References.- 3. Cell Coupling.- I. Introduction.- II. Which Molecules Diffuse from Cell to Cell.- A. Electrical Coupling.- B. Cell-to-Cell Diffusion of Ions.- C. Molecular Probes of Cell-to-Cell Coupling.- D. Metabolic Coupling.- E. Variability in Channel Permselectivity.- F. Asymmetry of Channel Permeability.- III. How Molecules Diffuse for Cell-to-Cell.- A. Gap Junction Architecture.- B. Structure of Cell-to-Cell Channels.- C. What Keeps Gap Junction Particles Aggregated.- D. Gap Junction Composition.- IV. How Cell-to-Cell Diffusion of Molecules is Regulated.- A. Uncoupling Agents.- B. Is Uncoupling a Graded Phenomenon?.- C. How to Enhance Coupling or Inhibit Uncoupling.- D. Change in Junction Structure with Uncoupling.- E. Hypotheses on Channel Closing Mechanisms.- F. Is Calmodulin Involved in the Regulation of Cell-to-Cell Coupling?.- References.- 4. Lipid Polymorphism and Membrane function.- I. Introduction.- II. Membrane Lipid Polymorphism: Technical Aspects.- III. Phase Preferences of Membrane Lipids.- IV. The Hexagonal HII Phase.- V. Modulation of Membrane Lipid Polymorphism.- A. One Lipid Systems.- B. Mixed Lipid Systems.- C. Lipid-Protein and Lipid-Peptide Interactions.- VI. "Isotropic" Lipid Structures and Lipid Particles.- VII. The Shape Concept, a Rationale for Lipid Polymorphism.- VIII. Functional Aspects of Lipid Polymorphism.- A. Fusion.- B. Transport.- C. Protein Insertion and Transport.- IX. Lipid Structure in Biological Membranes.- A. Erythrocyte Membrane.- B. Endoplasmic Reticulum (Microsomes).- C. The Inner Mitochondrial Membrane.- D. Bacterial Membranes.- E. Rod Outer Segment (ROS).- F. Chloroplast and Prolamellar Body.- G. Tight Junction.- X. Concluding Remarks.- References.- 5. Intrinsic Protein-Lipid Interactions in Biomembranes.- I. Introduction.- II. Properties of Biomembrane Components.- A. Lipids.- B. Proteins.- III. Lipid Composition and Enzyme Activity.- IV. Specificity of Protein-Lipid Interactions.- V. Distribution of Proteins in Membranes.- VI. Perturbation of Lipid Dynamics by Intrinisic Proteins.- A. NMR and EPR Spectroscopy.- B. Fluorescence Depolarization.- C. Range of the Perturbation.- VII. The Effect of Protein on Lipid Conformation.- A. Acyl Chain Region.- B. Glycerol Backbone Region.- C. Polar Region.- VIII. The Influence of Lipids on Protein Conformation.- IX. Diffusion of Membrane Components.- A. Lateral Diffusion.- B. Rotational Diffusion of Proteins.- X. Summary.- References.- 6. On the Molecular Structure of the Gramicidin Transmembrane Channel.- I. Introduction.- A. Primary Structure.- II. Planar Lipid Bilayer Transport Studies.- A. Phenomenology of Channel Transport.- B. Structural Implications of the Multiplicity of Single-Channel Conductances.- C. Structural Implications of Current/Voltage Curves.- D. Structural Deductions from Derivatives and Analogs.- III. Spectroscopic Characterization of the Lipid Incorporated Channel State.- A. Criteria for the Channel State in Lysolecithin Structures.- B. Relationship between the Lysolecithin-Gramicidin Heat Incorporated Channel State and the State of Gramicidin in Lipid Vesicles.- C. Orientation of Gramicidin Chains in the Lipid Bilayer.- D. Determining the Channel Conformation from Ion-Induced Carbonyl Carbon Chemical Shifts.- References.- 7. Conventional ESR Spectroscopy of Membrane Proteins: Recent Applications.- I. Introduction.- II. The Time Scale of Phospholipid Exchange at the Boundary of Non Aggregated Intrinsic Proteins.- III. Lipids Trapped between Protein Aggregates or Protein Oligomers.- IV. Specificity of Lipid-Protein Interactions as Investigated with Spin Labels.- A. 1st Approach: Estimation of the Relative Percentage of Immobilized Component.- B. 2nd Approach: Spin-Spin Interaction between Nitroxide Radicals.- V. Interactions between Extrinsic Proteins and Lipids.- A. Protein Penetration.- B. Protein Induction of Lateral Phospholipid Separation.- C. Protein Induction of Transverse Phospholipid Separation.- VI. Other Applications of Conventional ESR Spectroscopy to the Investigation of Membrane-Bound Enzymes.- A. Measurement of Surface Potentials and Intermembrane Potentials.- B. Conformation of Membrane-Bound Enzymes.- References.- 8. Saturation Transfer EPR Studies of Microsecond Rotational Motions in Biological Membranes.- I. Introduction.- II. ST-EPR Methodology.- A. General Principles of ST-EPR.- B. Methodology Used in Most Published Applications.- C. Recent Developments in ST-EPR Methodology.- III. Membrane-Bound Enzymes.- A. Sarcoplasmic Reticulum Calcium Transport ATPase.- B. Mitochondrial Electron Transport Chain.- C. Cytochrome P-450.- D. Glyceraldehyde-3-Phosphate Dehydrogenase.- IV. Other Membrane Proteins.- A. Rhodopsin.- B. Acetylcholine Receptor.- C. Red Blood Cell Membranes.- V. Lipid Probes.- VI. Summary.- References.- 9. Dye Probes of Cell, Organelle, and Vesicle Membrane Potentials.- I. Introduction.- II. Types of Potential Sensitive Dyes.- III. Slow Dyes.- A. Mechanism of Slow Dyes.- B. Examples of the Use of Slow Dyes.- IV. Fast Dyes.- A. General Properties.- B. Examples of the Uses of Fast Dyes.- References.- 10. Selective Covalent Modification of Membrane Components.- I. Introduction.- A. Aim and Purpose of Selective Covalent Modification.- B. Biological Membranes as Reactants in Chemical Reactions.- C. Selectivity-Promoting Factors in Membrane Labeling Studies.- II. Covalent Modification of Lipid Components.- A. Lipid Polar Head Group Modification.- B. Lipid Labeling Within the Apolar Membrane Phase.- III. Selective Covalent Modification of Protein Components.- A. Protein Modification Attained by Polar Reagent-Membrane Interaction.- B. Hydrophobic Labeling of Membrane Protein Components.- IV. Information Acquired through Selective Modification.- A. Membrane Structure: Sidedness, Asymmetry and Protein Topography.- B. Membrane Protein Function and Mechanism.- References.- 11. Calcium Ions, Enzymes, and Cell Fusion.- I. Introduction.- II. The Fusion of Myoblasts.- A. Dependence on Ca2+.- B. Some Recent Developments.- III. General Hypotheses: Ca2+, Phospholipids and Membrane Fusion.- A. Ca2+ and ATPase Activity.- B. Phase Separations of Membrane Lipids.- C. Nonbilayer Structures.- IV. Cell Fusion and Vesicle Fusion without Ca2+.- A. Cell Fusion.- B. Vesicle Fusion.- V. Concluding Comments.- References.- 12. Role of Membrane Fluidity in the Expression of Biological Functions.- I. Introduction.- II. Meaning and Measurement of Membrane Fluidity.- A. Definition of Fluidity and Viscosity of Ordinary Liquids.- B. Measurement of Membrane Fluidity through Fluorescence Anisotropy.- C. Measurement of the Conformation (Order) and Dynamics (Fluidity) of Membranes by NMR and ESR.- D. Limitations of the DPH Technique for Measuring Fluidity.- III. Factors that Influence Membrane Fluidity.- A. Lipid Composition.- B. Protein ard Boundary Lipid.- C. pH.- D. Calcium.- E. Salt Concentration.- IV. Mechanisms by which Membrane Fluidity Influences Membrane Functions.- V. Role of Membrane Fluidity in Some Membrane Functions.- A. Effects of Cholesterol.- B. Anesthetics.- C. Aging.- D. Cell Growth and Differentiation.- References.- 13. Rotational Diffusion of Membrane Proteins: Optical Methods.- I. Historical Background.- II. Physical Model for Rotational Diffusion of a Membrane Protein.- III. Physical Principles of Photoselection.- IV. Intrinsic and Extrinsic Probes.- V. Time-Resolved and Steady-State Methods.- VI. Linear Dichroism.- VII. Delayed Fluorescence.- VIII. Phosphorescence.- IX. Fluorescence Depletion.- X. Applications.- XI. Prospects.- References.