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Assembly of a Vectorially Oriented Four-Helix Bundle at the Air/Water Interface via Directed Electrostatic Interactions

TitleAssembly of a Vectorially Oriented Four-Helix Bundle at the Air/Water Interface via Directed Electrostatic Interactions
Publication TypeJournal Article
Year of Publication2003
AuthorsYe, S, Strzalka, J, Chen, X, Moser, CC, P. Dutton, L, J. Blasie, K
JournalLangmuirLangmuir
Volume19
Issue5
Pagination1515 - 1521
Date Published2003/03/01
ISBN Number0743-7463
Abstract

We sought to construct a monolayer composed of four-α-helical bundles formed by association of di-α-helical peptides. Specular X-ray reflectivity showed that dihelices that have been made amphiphilic by attachment of C16 hydrocarbon chains to their N-termini can be vectorially oriented in Langmuir monolayers at an air−water interface with their helical axes normal to the interface. But off-specular X-ray reflectivity indicated that these dihelices did not associate to form four-helix bundles possibly because they were constrained to be of parallel topology. To achieve four-helix bundles vectorially oriented at the interface, we relaxed this constraint to allow for a 1:1 association of the amphiphilic dihelices with their water-soluble counterparts. Electron density profiles for the monolayers derived from specular X-ray reflectivity demonstrated four-helix bundle formation only when the association between dihelices is directed via designed attractive electrostatic interactions between the polar faces of the amphipathic helices.We sought to construct a monolayer composed of four-α-helical bundles formed by association of di-α-helical peptides. Specular X-ray reflectivity showed that dihelices that have been made amphiphilic by attachment of C16 hydrocarbon chains to their N-termini can be vectorially oriented in Langmuir monolayers at an air−water interface with their helical axes normal to the interface. But off-specular X-ray reflectivity indicated that these dihelices did not associate to form four-helix bundles possibly because they were constrained to be of parallel topology. To achieve four-helix bundles vectorially oriented at the interface, we relaxed this constraint to allow for a 1:1 association of the amphiphilic dihelices with their water-soluble counterparts. Electron density profiles for the monolayers derived from specular X-ray reflectivity demonstrated four-helix bundle formation only when the association between dihelices is directed via designed attractive electrostatic interactions between the polar faces of the amphipathic helices.

URLhttp://dx.doi.org/10.1021/la026258f
Short TitleLangmuir