PROTEIN SIDE-CHAIN CONFORMATIONAL ENTROPY DERIVED FROM FUSION DATA - COMPARISON WITH OTHER EMPIRICAL SCALES

被引:37
作者
STERNBERG, MJE [1 ]
CHICKOS, JS [1 ]
机构
[1] DEPT CHEM, READING RG6 2AD, BERKS, ENGLAND
来源
PROTEIN ENGINEERING | 1994年 / 7卷 / 02期
关键词
FREE ENERGY; FUSION ENTROPY; HYDROPHOBICITY; MUTAGENESIS; PROTEIN STABILITY;
D O I
10.1093/protein/7.2.149
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The loss of conformational entropy of protein side-chains is a major effect in the energetics of folding. The simplest approach is to enumerate the number of freely rotatable bonds. Recently, two scales of side-chain conformational entropy have been proposed based on the definition of entropy as the Boltzmann sampling over all, accessible states (S = -R Sigma p(i)lnp(i), where p(i) is the probability of being in a rotameric state). In one scale, derived only for aliphatic and aromatic side-chains, the values of pi were obtained from Monte Carlo simulations. In the other scale, the observed frequencies of different rotameric states in a database of protein crystal structures yielded an estimate for p(i). Here an empirical estimation of the fusion entropy of the side-chains is used to derive a third scale. The fusion entropy is obtained as a sum of empirically derived contributions from component hydrocarbon and functional groups. There is a good agreement between the fusion scale and the other two scales. This suggests that the magnitude of conformational entropy is being correctly established.
引用
收藏
页码:149 / 155
页数:7
相关论文
共 34 条