Book contents
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Globular protein structure
- 3 Experimental methods
- 4 Thermodynamics and statistical mechanics
- 5 Protein–protein interactions
- 6 Theoretical studies of equilibrium
- 7 Nucleation theory
- 8 Experimental studies of nucleation
- 9 Lysozyme
- 10 Some other globular proteins
- 11 Membrane proteins
- 12 Crystallins and cataracts
- 13 Sickle hemoglobin and sickle cell anemia
- 14 Alzheimer's disease
- References
- Index
7 - Nucleation theory
Published online by Cambridge University Press: 01 October 2009
- Frontmatter
- Contents
- Preface
- 1 Introduction
- 2 Globular protein structure
- 3 Experimental methods
- 4 Thermodynamics and statistical mechanics
- 5 Protein–protein interactions
- 6 Theoretical studies of equilibrium
- 7 Nucleation theory
- 8 Experimental studies of nucleation
- 9 Lysozyme
- 10 Some other globular proteins
- 11 Membrane proteins
- 12 Crystallins and cataracts
- 13 Sickle hemoglobin and sickle cell anemia
- 14 Alzheimer's disease
- References
- Index
Summary
Classical nucleation theory
In this section we give a brief review of nucleation theories sufficient for understanding the following chapters. Very good reviews of nucleation theories can be found in refs. [208]–[212].
Nucleation is a stochastic process by which droplets of the new (stable) phase are formed in the background of the metastable phase. The stochastic nature of fluctuation means that the supersaturated system does not switch to the new stable state immediately; before this, a sufficiently large fluctuation with properties of the new phase should occur. This fluctuation is called a critical nucleus or critical droplet, and the formation of the droplet is called a nucleation event. Each nucleation event occurs randomly. The average rate of the nucleation events per unit of time per volume is called the nucleation rate. Homogeneous nucleation is the occurrence of nucleation events in the bulk, with no surfaces or impurities involved. Heterogeneous nucleation is nucleation that occurs on surfaces or impurities. Homogeneous nucleation is an intrinsic property of a system, whereas heterogeneous nucleation is not.
In the case of liquid condensation from vapor or crystallization from dilute solution, it is straightforward to identify the clusters of new phase, as they differ in density. However, this is not always the case.
- Type
- Chapter
- Information
- Protein CondensationKinetic Pathways to Crystallization and Disease, pp. 109 - 134Publisher: Cambridge University PressPrint publication year: 2007