期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1982
卷号:79
期号:15
页码:4545-4549
DOI:10.1073/pnas.79.15.4545
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:A simple dipole model is developed for estimation of the electrostatic interaction energy between alpha-helices in proteins. This model is used to estimate the electrostatic stabilization in a recurrent protein tertiary structural motif, an array of four closely packed alpha-helices. It is found that, for the proteins examined (cytochrome c', hemerythrin, myohemerythrin, cytochrome b562, and a T4 phage lysozyme domain), their common antiparallel arrangement of adjacent helices confers a stabilization of 5--7 kcal/mol (1 cal = 4.18 J). In contrast, a similarly packed array of parallel helices is relatively destabilized by 20 kcal/mol. These results show that helix-dipole interactions are important in the stabilization of this structural motif. These effects are discussed both in the context of folding pathways for 4-alpha-helical proteins and the stabilization of the higher aggregates.