Alpha-helical coiled coils represent a common protein oligomerization motif that are mainly stabilized by hydrophobic interactions occurring along their coiled-coil interface, the so-called hydrophobic seam. We have recently de novo designed and optimized a series of two-heptad repeat long coiled-coil peptides which are further stabilized by a complex network of inter- and intrahelical salt bridges. Here we have extended the de novo design of such two heptad-repeat long peptides by removing the central and most important g-e' Arg to Glu (g-e'RE) ionic interhelical interaction and replacing these residues by alanine residues. The effect of the missing interhelical ionic interaction on coiled-coil formation and stability has been analyzed by CD spectroscopy, analytical ultracentrifugation, and X-ray crystallography. We show that the peptide, while being highly alpha-helical, is no longer able to form a parallel coiled-coil structure but rather assumes an octameric globular helical assembly devoid of any coiled-coil interactions.
Removing an interhelical salt bridge abolishes coiled-coil formation in a de novo designed peptide.,Meier M, Lustig A, Aebi U, Burkhard P J Struct Biol. 2002 Jan-Feb;137(1-2):65-72. PMID:12064934[1]
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References
↑ Meier M, Lustig A, Aebi U, Burkhard P. Removing an interhelical salt bridge abolishes coiled-coil formation in a de novo designed peptide. J Struct Biol. 2002 Jan-Feb;137(1-2):65-72. PMID:12064934 doi:http://dx.doi.org/10.1006/jsbi.2002.4467
