@article {2415, title = {X-ray Crystal Analysis of a TASP: Structural Insights of a Cavitein Dimer}, journal = {Journal of the American Chemical Society}, volume = {131}, number = {21}, year = {2009}, note = {ISI Document Delivery No.: 451QOTimes Cited: 0Cited Reference Count: 75Freeman, Jon O. Lee, Woo Cheol Murphy, Michael E. P. Sherman, John C.}, month = {Jun}, pages = {7421-7429}, type = {Article}, abstract = {Cavitein Q4 is a template assembled synthetic protein designed for X-ray crystallographic analysis. It is based on a previous monomeric helical bundle cavitein (N1GG) that consists of four identical parallel helical peptides. Crystals that were grown in the presence of bromide ions were used to solve the initial phases via single-wavelength anomalous dispersion (SAD). A 1.4 angstrom resolution data set was then refined starting with the SAD phases to provide the crystal structure of cavitein Q4. The crystal structure revealed cavitein Q4 as an asymmetric dimer, although the cavitein appears to be largely monomeric in solution. A comparative analysis is carried out to discern any intrinsic differences between Q4 and its parent cavitein N1GG. We present herein the first X-ray crystal structure of a TASP system and relate this structure to the solution data for both Q4 and its parent N1GG.}, keywords = {4-HELIX BUNDLE, ALPHA-HELICES, ANALYTICAL, ANION-BINDING, ASSEMBLED SYNTHETIC PROTEINS, DE-NOVO PROTEINS, NATIVE-LIKE STRUCTURE, PEPTIDE-CAVITANDS, PROTEINS, SELF-ASSOCIATION, ULTRACENTRIFUGATION, UPPER RIM}, isbn = {0002-7863}, url = {://000266484900042}, author = {Freeman, J. O. and Lee, W. C. and Murphy, M. E. P. and Sherman, J. C.} } @article {4500, title = {Design of proteins using rigid organic macrocycles as scaffolds}, journal = {Bioorganic \& Medicinal Chemistry}, volume = {7}, number = {1}, year = {1999}, note = {ISI Document Delivery No.: 173QETimes Cited: 21Cited Reference Count: 39}, month = {Jan}, pages = {23-27}, type = {Article}, abstract = {We have designed and synthesized new three-helix template-assembled synthetic proteins (TASPs) 1a-c. The template was the rigid cyclotribenzylene (CTB) macrocycle 2, which has C-3 symmetry. Thiol moieties on the CTB template were used to link cysteine-containing peptide strands 3a-c via disulfide bonds. With designed peptide strands of 15 and 18 residues in length, the structure of TASPs 1a-c were determined to be helical in water according to circular dichroism (CD) spectroscopy. The helicities of TASPs la-e were unchanged over large ranges of pH (2-12) and salt concentrations (0-2 M KCl). TASPs 1a-c were also extremely resistant to chemical denaturants: it requires a guanidine hydrochloride (GnHCl) concentration of 7.4 M for TASPs 1a-c to lose 50\% of their helicity. The major force for stabilization of TASPs 1a-c is the hydrophobic bundling of the helices. (C) 1999 Elsevier Science Ltd. All rights reserved.}, keywords = {4-HELIX BUNDLE PROTEIN, ASSEMBLED SYNTHETIC PROTEINS, CHEMOSELECTIVE LIGATION, CONSTRUCTION, CROSS-LINKING, CRYSTAL-STRUCTURE, cyclotribenzylene, de novo protein, DE-NOVO PROTEINS, HELICAL BUNDLES, HELICAL PROTEIN, PEPTIDE, TASP, TEMPLATE}, isbn = {0968-0896}, url = {://000078990600004}, author = {Causton, A. S. and Sherman, J. C.} }