Local conformational relaxations and protein folding-unfolding transition

Journal Article · Wed Oct 01 00:00:00 EDT 1980 · Biophys. J.; (United States)

DOI:https://doi.org/10.1016/S0006-3495(80)84966-6· OSTI ID:6761109

Tsong, T Y; Kanehisa, M I

A protein molecule is a small system; as such its conformation constantly fluctuates. These events cover a broad time range: picoseconds for bond vibrations, oscillations and rotation, nanoseconds to microseconds for chain motions at a local level, and milliseconds to seconds for folding-unfolding transition. In a recent study we examined how events associated with rapid intramolecular motions or local conformational relaxations might affect the dynamics of the chain folding. We have proposed a cluster model which postulates that a peptide chain folds, under a favorable solvent condition, by first forming structural nuclei at locals, and second, merging or coalescing these nuclei into larger and more stable structural domains. The merging of local clusters is driven by solvent exclusion, i.e., by a hydrophobic effect. Fabrication of the detailed three dimensional arrangements within the newly forged hydrophobic core(s) is a consequence of this merging process. Calculations show that the cluster model is a two state model. However, each macrostate is a composite of microscopic states. Kinetics of interconversion of the two macroscopic states, as in the case of the folding-unfolding transition, are complex. These kinetics are determined by analyzing the initial distributions of the population and their movements toward the final distribution after a change in solvent conditions. Two pieces of information will be added to further clarify some basic features of the model.

• Research Organization: Johns Hopkins Univ., Baltimore, MD
• OSTI ID: 6761109
• Journal Information: Biophys. J.; (United States), Vol. 32:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PROTEINS
MOLECULAR STRUCTURE
ULTRASTRUCTURAL CHANGES
BIOCHEMICAL REACTION KINETICS
INTERMEDIATE STRUCTURE
INTERMOLECULAR FORCES
NUCLEATION
SOLVENT PROPERTIES
STRUCTURAL CHEMICAL ANALYSIS
THREE-DIMENSIONAL CALCULATIONS
TIME DEPENDENCE
VISCOSITY
KINETICS
MORPHOLOGICAL CHANGES
ORGANIC COMPOUNDS
REACTION KINETICS
550200* - Biochemistry