alpha-Helix dipole model and electrostatic stabilization of 4-alpha-helical proteins.
AUTOR(ES)
Sheridan, R P
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=346711Documentos Relacionados
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