A method is presented for determining the concentrations of peptides and proteins having isodichroic points near 203 nm. The existence of an isodichroic point for a given substance indicates a local two-state (a-helix, random coil) population. The mean residue ellipticity at the isodichroic point, [
Cooperativity of the helix–random coil transition determined from hydrodynamic data
✍ Scribed by Gary Hagnauer; Wilmer G. Miller
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1970
- Tongue
- English
- Weight
- 381 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
The approximations in the equation relating the viscosity of partially helical molecules to the cooperativity of the helix–random coil transition are investigated. Of the several approximations considered, only the neglect of long‐range intramolecular interactions in the random coil leads to significant error. This is a result of the inverse fourth‐power relationship between the assumed expansion factor and the cooperativity determined from analysis of experimental data. Upon approximately accounting for the random coil expansion, the experimental data of Ptitsyn et al. yield an ionic strength‐independent cooperativity in agreement with other methods.
📜 SIMILAR VOLUMES
The purpose of this paper is to examine and contrast several formulations of the partition function for the helix-coil transition of random-sequence nucleic acids. In the exact approach, the sequence of bases in a given molecule is fixed, but this leads to expressions which are difficult to evaluate