Structural studies of amphiphilic 4-helix bundle peptides incorporating designed extended chromophores for nonlinear optical biomolecular materials
Joseph Strzalka, Ting Xu, Andrey Tronin, Sophia P. Wu, Ivan Miloradovic, Ivan
Kuzmenko, Thomas Gog, Michael J. Therien, J. Kent Blasie
Extended conjugated chromophores containing (porphinato) zinc components that exhibit large optical polarizabilities and hyperpolarizabiliites are incorporated into amphiphilic 4-helix bundle peptides via specific axial histidyl ligation of the metal. The bundle's designed amphiphilicity enables vectorial orientation of the chromophore/peptide complex in macroscopic monolayer ensembles. The 4-helix bundle structure is maintained upon incorporation of two different chromophores at stoichiometries of 1-2 per bundle. The axial ligation site appears to effectively control the position of the chromophore along the length of the bundle.