Hydrogen Bonding in Biological Structures

IA Basic Concepts.- 1 The Importance of Hydrogen Bonds.- 1.1 Historical Perspective.- 1.2 The Importance of Hydrogen Bonds in Biological Structure and Function.- 1.3 The Role of the Water Molecules.- 1.4 Significance of Small Molecule Crystal Structural Studies.- 1.5 The Structural Approach.- 2 Definitions and Concepts.- 2.1 Definition of the Hydrogen Bond - Strong and Weak Bonds.- 2.2 Hydrogen-Bond Configurations: Two- and Three-Center Hydrogen Bonds; Bifurcated and Tandem Bonds.- 2.3 Hydrogen Bonds Are Very Different from Covalent Bonds.- 2.4 The van der Waals Radii Cut-Off Criterion Is Not Useful.- 2.5 The Concept of the Hydrogen-Bond Structure.- 2.6 The Importance of ? and ? Cooperativity.- 2.7 Homo-, Anti- and Heterodromic Patterns.- 2.8 Hydrogen Bond Flip-Flop Disorder: Conformational and Configurational.- 2.9 Proton-Deficient Hydrogen Bonds.- 2.10 The Excluded Region.- 2.11 The Hydrophobic Effect.- 3 Experimental Studies of Hydrogen Bonding.- 3.1 Infrared Spectroscopy and Gas Electron Diffraction.- 3.2 X-Ray and Neutron Crystal Structure Analysis.- 3.3 Treatment of Hydrogen Atoms in Neutron Diffraction Studies.- 3.4 Charge Density and Hydrogen-Bond Energies.- 3.5 Neutron Powder Diffraction.- 3.6 Solid State NMR Spectroscopy.- 4 Theoretical Calculations of Hydrogen-Bond Geometries.- 4.1 Calculating Hydrogen-Bond Geometries.- 4.2 Ab-Initio Molecular Orbital Methods.- 4.3 Application to Hydrogen-Bonded Complexes.- 4.4 Semi-Empirical Molecular Orbital Methods.- 4.5 Empirical Force Field or Molecular Mechanics Methods.- 5 Effect of Hydrogen Bonding on Molecular Structure.- IB Hydrogen-Bond Geometry.- 6 The Importance of Small Molecule Structural Studies.- 6.1 Problems Associated with the Hydrogen-Bond Geometry.- 6.2 The Hydrogen Bond Can Be Described Statistically.- 6.3 The Problems of Measuring Hydrogen-Bond Lengths and Angles in Small Molecule Crystal Structures.- 7 Metrical Aspects of Two-Center Hydrogen Bonds.- 7.1 The Metrical Properties of O-H *** O Hydrogen Bonds.- 7.1.1 Very Strong and Strong OH *** O Hydrogen Bonds Occur with Oxyanions, Acid Salts, Acid Hydrates, and Carboxylic Acids.- 7.1.2 OH *** O Hydrogen Bonds in the Ices and High Hydrates.- 7.1.3 Carbohydrates Provide the Best Data for OH ... O Hydrogen Bonds: Evidence for the Cooperative Effect.- 7.2 N-H *** O Hydrogen Bonds.- 7.3 N-H *** N Hydrogen Bonds.- 7.4 O-H *** N Hydrogen Bonds.- 7.5 Sequences in Lengths of Two-Center Hydrogen Bonds.- 7.6 H/D Isotope Effect.- 8 Metrical Aspects of Three- and Four-Center Hydrogen Bonds.- 8.1 Three-Center Hydrogen Bonds.- 8.2 Four-Center Hydrogen Bonds.- 9 Intramolecular Hydrogen Bonds.- 10 Weak Hydrogen-Bonding Interactions Formed by C-H Groups as Donors and Aromatic Rings as Acceptors.- 11 Halides and Halogen Atoms as Hydrogen-Bond Acceptors.- 12 Hydrogen-Bond Acceptor Geometries.- II Hydrogen Bonding in Small Biological Molecules.- 13 Hydrogen Bonding in Carbohydrates.- 13.1 Sugar Alcohols (Alditols) as Model Cooperative Hydrogen-Bonded Structures.- 13.2 Influence of Hydrogen Bonding on Configuration and Conformation in Cyclic Monosaccharides.- 13.3 Rules to Describe Hydrogen-Bonding Patterns in Monosaccharides.- 13.4 The Water Molecules Link Hydrogen-Bond Chains into Nets in the Hydrated Monosaccharide Crystal Structures.- 13.5 The Disaccharide Crystal Structures Provide an Important Source of Data About Hydrogen-Bonding Patterns in Polysaccharides.- 13.6 Hydrogen Bonding in the Tri- and Tetrasaccharides Is More Complex and Less Well Defined.- 13.7 The Hydrogen Bonding in Polysaccharide Fiber Structures Is Poorly Defined.- 14 Hydrogen Bonding in Amino Acids and Peptides: Predominance of Zwitterions.- 15 Purines and Pyrimidines.- 15.1 Bases Are Planar and Each Contains Several Different Hydrogen-Bonding Donor and Acceptor Groups.- 15.2 Many Tautomeric Forms Are Feasible But Not Observed.- 15.3 ?-Bond Cooperativity Enhances Hydrogen-Bonding Forces.- 15.4 General, Non-Base-Pairing Hydrogen Bonds.- 16 Base Pairing in the Purine and Pyrimidine Crystal Structures.- 16.1 Base-Pair Configurations with Purine and Pyrimidine Homo-Association.- 16.2 Base-Pair Configurations with Purine-Pyrimidine Hetero-Association: the Watson-Crick Base-Pairs.- 16.3 Base Pairs Can Combine to Form Triplets and Quadruplets.- 17 Hydrogen Bonding in the Crystal Structures of the Nucleosides and Nucleotides.- 17.1 Conformational and Hydrogen-Bonding Characteristics of the Nucleosides and Nucleotides.- 17.2 A Selection of Cyclic Hydrogen-Bonding Patterns Formed in Nucleoside and Nucleotide Crystal Structures.- 17.3 General Hydrogen-Bonding Patterns in Nucleoside and Nucleotide Crystal Structures.- III Hydrogen Bonding in Biological Macromolecules.- 18 O-H *** O Hydrogen Bonding in Crystal Structures of Cyclic and Linear Oligoamyloses: Cyclodextrins, Maltotriose, and Maltohexaose.- 18.1 The Cyclodextrins and Their Inclusion Complexes.- 18.2 Crystal Packing Patterns of Cyclodextrins Are Determined by Hydrogen Bonding.- 18.3 Cyclodextrins as Model Compounds to Study Hydrogen-Bonding Networks.- 18.4 Cooperative, Homodromic, and Antidromic Hydrogen-Bonding Patterns in the ?-Cyclodextrin Hydrates.- 18.5 Homodromic and Antidromic O-H *** O Hydrogen-Bonding Systems Analyzed Theoretically.- 18.6 Intramolecular Hydrogen Bonds in the ?-Cyclodextrin Molecule are Variable - the Induced-Fit Hypothesis.- 18.7 Flip-Flop Hydrogen Bonds in ?-Cyclodextrin * 11 H2O.- 18.8 From Flip-Flop Disorder to Ordered Homodromic Arrangements at Low lbmperature: The Importance of the Cooperative Effect.- 18.9 Maltohexaose Polyiodide and Maltotriose - Double and Single Left-Handed Helices With and Without Intramolecular O(2) *** O(3?) Hydrogen Bonds.- 19 Hydrogen Bonding in Proteins.- 19.1 Geometry of Secondary-Structure Elements: Helix, Pleated Sheet, and Turn.- 19.2 Hydrogen-Bond Analysis in Protein Crystal Structures.- 19.3 Hydrogen-Bonding Patterns in the Secondary Structure Elements.- 19.4 Hydrogen-Bonding Patterns Involving Side-Chains.- 19.5 Internal Water Molecules as Integral Part of Protein Structures.- 19.6 Metrical Analysis of Hydrogen Bonds in Proteins.- 19.7 Nonsecondary-Structure Hydrogen-Bond Geometry Between Main-Chains, Side-Chains and Water Molecules.- 19.8 Three-Center (Bifurcated) Bonds in Proteins.- 19.9 Neutron Diffraction Studies on Proteins Give Insight into Local Hydrogen-Bonding Flexibility.- 19.10 Site-Directed Mutagenesis Gives New Insight into Protein Thermal Stability and Strength of Hydrogen Bonds.- 20 The Role of Hydrogen Bonding in the Structure and Function of the Nucleic Acids.- 20.1 Hydrogen Bonding in Nucleic Acids is Essential for Life.- 20.2 The Structure of DNA and RNA Double Helices is Determined by Watson-Crick Base-Pair Geometry.- 20.3 Systematic and Accidental Base-Pair Mismatches: "Wobbling" and Mutations.- 20.4 Noncomplementary Base Pairs Have a Structural Role in tRNA.- 20.5 Homopolynucleotide Complexes Are Stabilized by a Variety of Base-Base Hydrogen Bonds - Three-Center (Bifurcated) Hydrogen Bonds in A-Tracts.- 20.6 Specific Protein-Nucleic Acid Recognition Involves Hydrogen Bonding.- IV Hydrogen Bonding by the Water Molecule.- 21 Hydrogen-Bonding Patterns in Water, Ices, the Hydrate Inclusion Compounds, and the Hydrate Layer Structures.- 21.1 Liquid Water and the Ices.- 21.2 The Hydrate Inclusion Compounds.- 21.3 Hydrate Layer Structures.- 22 Hydrates of Small Biological Molecules: Carbohydrates, Amino Acids, Peptides, Purines, Pyrimidines, Nucleosides and Nucleotides.- 23 Hydration of Proteins.- 23.1 Characterization of "Bound Water" at Protein Surfaces - the First Hydration Shell.- 23.2 Sites of Hydration in Proteins.- 23.3 Metrics of Water Hydrogen Bonding to Proteins.- 23.4 Ordered Water Molecules at Protein Surfaces - Clusters and Pentagons.- 24 Hydration of Nucleic Acids.- 24.1 Two Water Layers Around the DNA Double Helix.- 24.2 Crystallographically Determined Hydration Sites in A-, B-, Z-DNA. A Statistical Analysis.- 24.3 Hydration Motifs in Double Helical Nucleic Acids.- 24.3.1 Sequence-Independent Motifs.- 24.3.2 Sequence-Dependent Motifs.- 24.4 DNA Hydration and Structural Transitions Are Correlated: Some Hypotheses.- 25 The Role of Three-Center Hydrogen Bonds in the Dynamics of Hydration and of Structure Transition.- References.- Refcodes.