Toward the development of site-switchable DNA-binding peptides with built-in functionality for late-stage dimerization by 1,3-dipolar cycloaddition

CHED 513

Donald P. Curran III, dcurran6@naz.edu1, Veronica Dodero2, Timm A. Knoerzer, tknoerz7@naz.edu1, and J. L. Mascareñas, qojoselm@usc.es3. (1) Department of Chemistry, Nazareth College of Rochester, 4245 East Avenue, Rochester, NY 14618, (2) Depto de Qca-INIQO, Universidad Nacional del Sur, Av. Alem 1253, Bahía Blanca, 8000, Argentina, (3) Organic Chemistry Department, University of Santiago de Compostela, Avda. de las Ciencias s/n, 15706 Santiago de Compostela, Spain
Basic region leucine zipper (bZip) proteins such as the yeast transcription activator GCN4 contain a bipartite DNA-binding motif consisting of a coiled-coil leucine zipper dimerization domain and a highly charged basic region that directly contacts DNA. The monomeric basic region appears to be unfolded in the absence of DNA, but assumes a helical structure upon sequence-specific binding as a homodimer to a DNA recognition site. Replacement of the leucine zipper region by a disulfide bond at the C-terminus leads to peptides which maintain their sequence specificity recognizing both AP-1 (ATGAcTCAT) and CRE (ATGAcgTCAT) sites with high affinity at 4 ºC. In order to extend the reach of this work, we have envisioned synthetic mini-proteins in which dimerization can be facilitated by the use of a 1,3-dipolar cycloaddition (Click) reaction. Herein, we report the development of site-switchable DNA-binding peptides which have been modified with alkyne or azide containing amino acids at the C-terminus of the mini-protein. The alkyne or azide groups can be exploited in a late-stage 1,3-dipolar cycloaddition reaction as the critical step leading to artificial dimerization.