Is there a unique melting temperature for two-state proteins?
✍ Scribed by D. K. Klimov; D. Thirumalai
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 134 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0192-8651
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Thermal unfolding (or folding) in many proteins occurs in an apparent two‐state manner, suggesting that only two states, unfolded and folded, are populated. At the melting temperature, T~m~, the two states coexist. Using lattice models with side chains we show that individual residues become structured at temperatures that deviate from T~m~, which implies that partially folded conformations make substantial contribution to thermodynamic properties of two‐state proteins. We also find that the folding cooperativity for a given residue is linked to its accessible surface area. These results are consistent with the experiments on GCN4‐like zipper peptide, which showed that local melting temperatures differ from T~m~. Analysis of thermal unfolding of six proteins shows that Δ__T__/T~m~∼N^−1^, where Δ__T__ is the transition width and N is the number of residues. This scaling allows us to conclude that, when corrected for finite size effects, folding cooperativity can be captured using coarse grained models. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 161–165, 2002