Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgements
- Chapter 1 Global transitions in proteins
- Chapter 2 Molecular forces in biological structures
- Chapter 3 Conformations of macromolecules
- Chapter 4 Molecular associations
- Chapter 5 Allosteric interactions
- Chapter 6 Diffusion and Brownian motion
- Chapter 7 Fundamental rate processes
- Chapter 8 Association kinetics
- Chapter 9 Multi-state kinetics
- Chapter 10 Enzyme catalysis
- Chapter 11 Ions and counterions
- Chapter 12 Fluctuations
- Chapter 13 Ion permeation and membrane potential
- Chapter 14 Ion permeation and channel structure
- Chapter 15 Cable theory
- Chapter 16 Action potentials
- Appendix 1 Expansions and series
- Appendix 2 Matrix algebra
- Appendix 3 Fourier analysis
- Appendix 4 Gaussian integrals
- Appendix 5 Hyperbolic functions
- Appendix 6 Polar and spherical coordinates
- References
- Index
Chapter 4 - Molecular associations
Published online by Cambridge University Press: 24 May 2010
- Frontmatter
- Contents
- Preface
- Acknowledgements
- Chapter 1 Global transitions in proteins
- Chapter 2 Molecular forces in biological structures
- Chapter 3 Conformations of macromolecules
- Chapter 4 Molecular associations
- Chapter 5 Allosteric interactions
- Chapter 6 Diffusion and Brownian motion
- Chapter 7 Fundamental rate processes
- Chapter 8 Association kinetics
- Chapter 9 Multi-state kinetics
- Chapter 10 Enzyme catalysis
- Chapter 11 Ions and counterions
- Chapter 12 Fluctuations
- Chapter 13 Ion permeation and membrane potential
- Chapter 14 Ion permeation and channel structure
- Chapter 15 Cable theory
- Chapter 16 Action potentials
- Appendix 1 Expansions and series
- Appendix 2 Matrix algebra
- Appendix 3 Fourier analysis
- Appendix 4 Gaussian integrals
- Appendix 5 Hyperbolic functions
- Appendix 6 Polar and spherical coordinates
- References
- Index
Summary
The preceding chapters treated molecules as isolated entities. Now we will look at how molecules interact with one another. In biological systems molecules are continually binding together and coming apart. Molecular associations are the first step in most forms of biological signaling, as well as in enzyme catalysis. Hormones, neurotransmitters, second messengers, and metabolites bind to proteins to regulate their activity. Pharmacology is rooted in the molecular association between drugs and receptors. On a larger scale, associations between macromolecules direct the assembly of organelles. Here, we will examine the thermodynamic and statistical mechanical principals underlying chemical association processes. These concepts will serve as a useful prelude to the theory of allosteric interactions in the following chapter.
There are two guiding principles in understanding association processes in molecular biology. (1) The forces that control associations are usually noncovalent. These kinds of forces were covered in Chapter 2. Here we will discuss how noncovalent interactions such as electrostatic forces, hydrogen bonds, and hydrophobic interactions combine in various ways to stabilize molecular complexes. (2) Associations are stereospecific, and depend on a precise spatial arrangement of the interacting groups. A binding site within a protein is viewed as a lock, and a ligand that fits into this binding site is a key. As a result biological associations are highly specific; molecules can recognize one another and distinguish subtle variations in structure.
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- Information
- Molecular and Cellular Biophysics , pp. 89 - 110Publisher: Cambridge University PressPrint publication year: 2006