@article {2270, title = {Capillary electrophoresis frontal analysis for characterization of alpha(v)beta(3) integrin binding interactions}, journal = {Analytical Chemistry}, volume = {80}, number = {9}, year = {2008}, note = {ISI Document Delivery No.: 295JXTimes Cited: 8Cited Reference Count: 33Sun, Ying Cressman, Sonya Fang, Ning Cullis, Pieter R. Chen, David D. Y.}, month = {May}, pages = {3105-3111}, type = {Article}, abstract = {The specific binding characteristics of alpha(v)beta(3) integrins with an arginine-glycine-aspartic-acid (RGD) containing fluorescently labeled cyclic peptide is investigated with capillary electrophoresis-frontal analysis method. The new algorithm used to calculate the binding constants and binding stoichiometry was derived without the assumptions made in the commonly used Scatchard Plot method, thus enabling the determination of specific binding parameters in the presence of nonspecific binding. The a,6,3 integrin, a membrane protein, was studied in solution, without the need of immobilization or any other kind of modification. An RGD containing fluorescently labeled cyclic pentapeptide is used as the ligand with both specific and nonspecific binding characteristics, and an arginine-alanine-aspartic-acid (RAD) containing peptide is used as the control for nonspecific binding. While a typical specific binding isotherm has a shape of a rectangular hyperbola, a nonspecific binding isotherm is linear in the same ligand concentration region. A 1:2 specific binding stoichiometry was revealed with the second binding having a similar affinity compared to the first binding event.}, keywords = {ANGIOGENESIS, BEHAVIOR, CONSTANTS, CYCLIC RGD PEPTIDES, DRUG-PROTEIN-BINDING, INTEGRIN ALPHA(V)BETA(3), PRINCIPLES, RECOGNITION, TRANSDUCTION}, isbn = {0003-2700}, url = {://000255471900011}, author = {Sun, Y. and Cressman, S. and Fang, N. and Cullis, P. R. and Chen, D. D. Y.} } @article {2013, title = {G(boolean AND)C quartet - A DNA-inspired Janus-GC heterocycle: Synthesis, structural analysis, and self-organization}, journal = {Journal of the American Chemical Society}, volume = {130}, number = {39}, year = {2008}, note = {ISI Document Delivery No.: 353GITimes Cited: 7Cited Reference Count: 32Asadi, Ali Patrick, Brian O. Perrin, David M.}, month = {Oct}, pages = {12860-+}, type = {Article}, abstract = {In this communication we disclose the synthesis and characterization of a DNA-inspired self-complementary heterocycle that contains AAD-DAA H-bond acceptor/donor patterns. Whereas in the past such AAD-DAA self-complementarity has given rise to trimeric and hexameric rosettes, we now demonstrate that the same H-bonding scheme, when properly arrayed, can be used to program a tetrameric rosette, which unlike a G-quartet requires no metal binding or peripheral components for p reorganization. Of note, we exploit both 2D-NOESY and DOSY H-1 NMR to substantiate the tetrameric stoichiometry in this noncovalent rosette comprising 12 H-bonds.}, keywords = {BASE, CHEMISTRY, COMPLEXES, DERIVATIVES, FOLIC-ACID SALTS, HELICAL ROSETTE NANOTUBES, HYDROGEN-BONDED NETWORKS, MOLECULAR TECTONICS, RECOGNITION, solid-state structures}, isbn = {0002-7863}, url = {://000259553700012}, author = {Asadi, A. and Patrick, B. O. and Perrin,David M.} } @article {541, title = {Inhibitory module of Ets-1 allosterically regulates DNA binding through a dipole-facilitated phosphate contact}, journal = {Journal of Biological Chemistry}, volume = {277}, number = {3}, year = {2002}, note = {ISI Document Delivery No.: 514CWTimes Cited: 21Cited Reference Count: 50}, month = {Jan}, pages = {2225-2233}, type = {Article}, abstract = {DNA binding of the transcription factor Ets-1 is negatively regulated by three inhibitory helices that lie near the ETS domain. The current model suggests that this negative regulation, termed autoinhibition, is caused by the energetic expense of a DNA-induced structural transition that includes the unfolding of one inhibitory helix. This report investigates the role of helix H1 of the ETS domain in the autoinhibition mechanism. Previous structural studies modeled the inhibitory helices packing together and connecting with helix H1, suggesting a role of this helix in the configuration of an inhibitory module. Recently, high-resolution structures of the ETS domain-DNA interface indicate that the N terminus of helix H1 directly contacts DNA. The contact, which is augmented by the macrodipole of helix H1, consists of a hydrogen bond between the amide NH of leucine 337 in helix HI and the oxygen of a corresponding phosphate. We propose that this hydrogen bond positions helix H1 to be a link between autoinhibition and DNA binding. Four independent approaches tested this hypothesis. First, the hydrogen bond was disrupted by removal of the phosphate in a missing phosphate analysis. Second, base pairs that surround the helix HI-contacting phosphate and appear to dictate DNA backbone conformation were mutated. Next, a hydrophobic residue in helix H1 that is expected to position the N terminus of the helix was altered. Finally, a residue on the surface of helix 111 that may contact the inhibitory elements was changed. In each case DNA binding and autoinhibition was affected. Taken together, the results demonstrate the role of the dipole-facilitated phosphate contact in DNA binding. Furthermore, the findings support a model in which helix H1 links the inhibitory elements to the ETS domain. We speculate that this helix, which is conserved in all Ets proteins, provides a common route to regulation.}, keywords = {ALPHA-HELIX, AUTO-INHIBITION, COMPLEX, DOMAIN, FACTORS ELK-1, INDIRECT READOUT, MURINE ETS-1, PROTEINS, RECOGNITION, TRANSCRIPTION FACTOR}, isbn = {0021-9258}, url = {://000173421300083}, author = {Wang, H. and McIntosh, L. P. and Graves, B. J.} } @article {4647, title = {The structures of the neurotrophin 4 homodimer and the brain-derived neurotrophic factor/neurotrophin 4 heterodimer reveal a common Trk-binding site}, journal = {Protein Science}, volume = {8}, number = {12}, year = {1999}, note = {ISI Document Delivery No.: 266RPTimes Cited: 24Cited Reference Count: 45}, month = {Dec}, pages = {2589-2597}, type = {Article}, abstract = {The neurotrophins are growth factors that are involved in the development and survival of neurons. Neurotrophin release by a target tissue results in neuron growth along the neurotrophin concentration gradient, culminating in the eventual innervation of the target tissue. These activities are mediated through trk cell surface receptors. We have determined the structures of the heterodimer formed between brain-derived neurotrophic factor (BDNF) and neurotrophin 4 (NT4), as well as the structure of homodimer of NT4. We also present the structure of the Neurotrophin 3 homodimer, which is refined to higher resolution than previously published. These structures provide the first views of the architecture of the NT4 protomer. Comparison of the surface of a model of the BDNF homodimer with the structures of the neurotrophin homodimers reveals common features that may be important in the binding between the neurotrophins and their receptors. In particular, there exists an analogous region on the surface of each neurotrophin that is likely to be involved in trk receptor binding. Variations in sequence on the periphery of this common region serve to confer trk receptor specificity.}, keywords = {BDNF, CELLS, CRYSTAL-STRUCTURE, CRYSTALLOGRAPHY, DIFFERENTIATION, nerve growth factor, NERVE GROWTH-FACTOR, NGF, PURIFICATION, RECEPTOR, RECEPTORS, RECOGNITION, SPECIFICITY}, isbn = {0961-8368}, url = {://000084314100005}, author = {Robinson, R. C. and Radziejewski, C. and Spraggon, G. and Greenwald, J. and Kostura, M. R. and Burtnick, L. D. and Stuart, D. I. and Choe, S. and Jones, E. Y.} } @article {4395, title = {UDP-N-trifluoroacetylglucosamine as an alternative substrate in N-acetylglucosaminyltransferase reactions}, journal = {Carbohydrate Research}, volume = {306}, number = {1-2}, year = {1998}, note = {ISI Document Delivery No.: 100VZTimes Cited: 15Cited Reference Count: 28}, month = {Jan}, pages = {127-136}, type = {Article}, abstract = {The synthesis of UDP-N-trifluoroacetylglucosamine [uridine 5{\textquoteright}-(2-trifluoroacetamido-2-deoxy-alpha-D-glucopyranosyl diphosphate, UDP-GlcNAc-F-3] is reported. The compound is found to serve as a substrate for the {\textquoteright}core-2{\textquoteright} GlcNAc transferase (EC 2.4.1.102) that is involved in the biosynthesis, of O-linked glycoproteins and for the GlcNAcT-V transferase (EC 2.4. 1.155) that is a key biosynthetic enzyme controlling the branching pattern of cell surface complex Asn-linked oligosaccharides. The trisaccharide beta-o-Gal p-(1 {\textendash}> 3)-[beta-D-GlcpNAc-F-3(1 {\textendash}> 6)]alpha-D-GalpNAc-OR [R = (CH2)(8)CO2Me] was prepared from beta-D-Galp-(1 {\textendash}> 3)-alpha-D-GalpNAc-OR using the {\textquoteright}core-2{\textquoteright} GlcNAc transferase. The tetrasaccharide beta-D-GlcpNAc-(1 {\textendash}> 2)-[beta-D-GlcpNAc-F-3-(1 {\textendash}> 6)]-alpha-D-Manp-(1 {\textendash}> 6)-beta-D-Glcp-OR [R = (CH2)(7)CH3] was prepared from beta-D-GlcpNAc-(1 {\textendash}> 2)-alpha-D-Manp-(1 {\textendash}> 6)-beta-D-Glcp-OR [R = (CH2)(7)CH3] using the GlcNAcT-V transferase. Removal of the trifluoroacetyl group was achieved under mild basic conditions to give the corresponding glucosamine containing tetrasaccharide. These examples demonstrate the feasibility of introducing masked forms of glucosamine residues into oligosaccharides using GlcNAc-specific transferases. The requirement for the trifluoroacetamido group as a specific recognition element was evident in the observation that neither UDP-glucosamine nor UDP-glucose served as a donor substrates for the {\textquoteright}core-2{\textquoteright} GlcNAc transferase. (C) 1998 Elsevier Science Ltd. All rights reserved.}, keywords = {GLYCOPROTEINS, N-acetylglucosaminyltransferase, OLIGOSACCHARIDE, OLIGOSACCHARIDES, ORGANIC-SYNTHESIS, RECOGNITION, SYNTHESIS, UDP-sugar analog}, isbn = {0008-6215}, url = {://000074837200012}, author = {Sala, R. F. and MacKinnon, S. L. and Palcic, M. M. and Tanner, M. E.} } @article {4351, title = {Water-soluble cavitands: Synthesis of methylene-bridged resorcin[4]arenes containing hydroxyls and phosphates at their feet and bromomethyls and thiomethyls at their rims}, journal = {Journal of Organic Chemistry}, volume = {63}, number = {20}, year = {1998}, note = {ISI Document Delivery No.: 127ZGTimes Cited: 11Cited Reference Count: 31}, month = {Oct}, pages = {6824-6829}, type = {Article}, abstract = {The synthesis of rim-functionalized methylene-bridged resorcin[4]arenes ("cavitands") containing hydrophilic propanol or water-solublilizing propylphosphate feet is described. The cavitands possess the synthetically useful benzylthiol (cavitands 6 and 16) or benzylbromide (cavitands 9 and 11) functionalities at their rims, which are suitable for further derivatization near the hydrophobic cavity of the cavitand. These water-soluble cavitands represent new building blocks that are ideal for use in aqueous supramolecular chemistry. As an example of their synthetic utility in supramolecular studies, we have reacted phosphate-footed cavitands 11 and 16 with cysteine-containing peptide 17 and chloroacetylated peptide 19, respectively, to afford the corresponding de novo proteins 18 and 20.}, keywords = {ADSORPTION, BUILDING-BLOCKS, CARCERANDS, ENCAPSULATION, HOST-GUEST COMPLEXATION, MOLECULAR, PHASE, RECOGNITION, RESORCINARENES, SELF-ASSEMBLED MONOLAYERS}, isbn = {0022-3263}, url = {://000076380300019}, author = {Mezo, A. R. and Sherman, J. C.} } @article {3278, title = {TEMPLATION EFFECTS ON FORMATION OF A HEMICARCEPLEX}, journal = {Supramolecular Chemistry}, volume = {5}, number = {1}, year = {1995}, note = {ISI Document Delivery No.: RX096Times Cited: 15Cited Reference Count: 36}, pages = {31-37}, type = {Article}, abstract = {We have shown previously that the reaction to form carceplex 3 . guest has dramatic templation requirements where the best template molecule studied is one million times more effective at bridging the two bowl-shaped precursors than the poorest template. Here, we investigate the template requirements for the formation of hemicarceplex 4 . guest which is similar to carceplex 3 . guest in cavity size and shape. The two compounds differ in that 4 . guest lacks one of the four inter-bowl methylene bridges and thus has a portal and reduced symmetry relative to carceplex 3 . guest (C-2v vs D-4h). Thus, the template requirements for hemicarceplex 4 . guest are more stringent because the two howls can, in principle, misalign. We have found that despite these differences, the same template effect holds. We conclude that the same forces are at play in each reaction. These forces include 1) favorable van der Waals interactions between the template molecule and the forming cavity of the carceplex or hemicarceplex 2) unfavorable steric strain being imparted to the complex and 3) hydrogen bonds between the bowls. We also demonstrate the utility of matrix-assisted laser desorption ionization (MALDI) as a mild mass spectrometric technique for non-volatile organic compounds and complexes.}, keywords = {4 PORTALS, BINDING, CAPTURE, CARCERANDS, CONSTRICTIVE, HOST-GUEST COMPLEXATION, LASER DESORPTION IONIZATION, MASS-SPECTROMETRY, POLYMERS, RECOGNITION, RELEASE}, isbn = {1061-0278}, url = {://A1995RX09600007}, author = {Chopra, N. and Sherman, J. C.} }