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College Park, Maryland      June 6 - 10 , 2004

T1-B1 (8:30 AM): X-ray & Neutron Reflectivity Studies of Vectorially-Oriented 4-Helix Bundle Maquette Peptides (Invited)

J. K. Blasie, S. Ye, J. Strzalka (Department of Chemistry, University of Pennsylvania)

Bundles of alpha-helices provide a scaffold for binding prosthetic groups at selected locations within the structure to mimic functions exhibited by biological proteins. For example, histidine residues can be strategically placed for the axial ligation of metalloporphyrin prosthetic groups involved in biological electron transfer reactions. The first designed artificial peptides, prepared by solid-phase chemical synthesis, used amphipathic di-helices which self-assembled in aqueous solution forming 4-helix bundles. These were called “maquettes” and they exhibited exceptional stabilities relative to their natural counterparts. Nevertheless, to realize any device applications based on their functionality, the peptides must be vectorially-oriented in an ensemble, e.g., at an interface. Incorporation of non-biological prosthetic groups further allows for the possibility of novel functionality and related device applications. Several examples will be provided concerning maquette design for vectorial orientation at soft interfaces. Both x-ray and neutron scattering techniques are key to ascertaining the detailed nature of these maquette structures and their vectorial orientation at soft interfaces. Each of these techniques has distinct advantages and disadvantages.

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