Time scale, geometrical constraints, and disulfide bond formation in the folding of small globular proteins
✍ Scribed by Andrzej Gałat
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1985
- Tongue
- English
- Weight
- 383 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
We hypothesize a model of protein folding based on the Poincare recursion argument and a number of experimental results, including CD, nmr, and Raman spectra. Our model considers that protein folding in uiuo proceeds through prefolded peptide segments consisting of 3 to 14 amino acid residues. Such segments may fold spontaneously into nativelike microdomains within a biologically feasible time, i.e., in the 10-6-10-1 s time scale. If, due to improper recognition and adjustment of their surfaces, these transiently formed secondary structures are not stabilized by long-range interactions, then the protein species occur within a time-and number-averaged spectrum of populations of transient conformational substates until the final, proper adjustment of the segments takes place. However, if, during protein folding, incorrect disulfide (SS) bonds are formed, then such unique through-space contacts between the different parts of the polypeptide chain are usually restricted to a minimum. It is postulated that unfolding and refolding processes in uitro, and protein folding in uiuo, proceed through variably populated quantized substates. The distribution of these substates depends on a number of molecultis interactions between the phase and the hydration spheres surrounding the prefolded surfaces of peptide segments and long-range interactions between these prefolded surfaces.
* Dedicated to Professor Elkan R. Blout on the occasion of his sixty-fifth birthday.