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Full-Text Articles in Physical Sciences and Mathematics
Fluorogenic Atom Transfer Radical Polymerization In Aqueous Media As A Strategy For Detection, Zachary T. Allen, Jemima R. Sackey-Addo, Madeline P. Hopps, Danyal Tahseen, Joseph T. Anderson, Tyler A. Graf, Christina B. Cooley
Fluorogenic Atom Transfer Radical Polymerization In Aqueous Media As A Strategy For Detection, Zachary T. Allen, Jemima R. Sackey-Addo, Madeline P. Hopps, Danyal Tahseen, Joseph T. Anderson, Tyler A. Graf, Christina B. Cooley
Chemistry Faculty Research
The development of novel approaches to signal amplification in aqueous media could enable new diagnostic platforms for the detection of water-soluble analytes, including biomolecules. This paper describes a fluorogenic polymerization approach to amplify initiator signal by the detection of visible fluorescence upon polymerization in real-time. Fluorogenic monomers were synthesized and co-polymerized by atom transfer radical polymerization (ATRP) in water to reveal increasing polymer fluorescence as a function of both reaction time and initiator concentration. Optimization of the fluorogenic ATRP reaction conditions allowed for the quantitative detection of a small-molecule initiator as a model analyte over a broad linear concentration range …
Molecular Recognition Of Methionine-Terminated Peptides By Cucurbit[8]Uril, Zoheb Hirani, Hailey F. Taylor, E. F. Babcock, Andrew T. Bockus, C. D. Varnado Jr., Christopher W. Bielawski, Adam R. Urbach
Molecular Recognition Of Methionine-Terminated Peptides By Cucurbit[8]Uril, Zoheb Hirani, Hailey F. Taylor, E. F. Babcock, Andrew T. Bockus, C. D. Varnado Jr., Christopher W. Bielawski, Adam R. Urbach
Chemistry Faculty Research
This Article describes the molecular recognition of peptides containing an N-terminal methionine (Met) by the synthetic receptor cucurbit[8]-uril (Q8) in aqueous solution and with submicromolar affinity. Prior work established that Q8 binds with high affinity to peptides containing aromatic amino acids, either by simultaneous binding of two aromatic residues, one from each of two different peptides, or by simultaneous binding of an aromatic residue and its immediate neighbor on the same peptide. The additional binding interface of two neighboring residues suggested the possibility of targeting nonaromatic peptides, which have thus far bound only weakly to synthetic receptors. A peptide library …
Cucurbit[7]Uril-Tetramethylrhodamine Conjugate For Direct Sensing And Cellular Imaging, Andrew T. Bockus, Lauren C. Smith, Amy G. Grice, Omar A. Ali, Carolyn C. Young, William Mobley, Ashley Leek, James Lewis Roberts, Brittany Vinciguerra, Lyle D. Isaacs, Adam R. Urbach
Cucurbit[7]Uril-Tetramethylrhodamine Conjugate For Direct Sensing And Cellular Imaging, Andrew T. Bockus, Lauren C. Smith, Amy G. Grice, Omar A. Ali, Carolyn C. Young, William Mobley, Ashley Leek, James Lewis Roberts, Brittany Vinciguerra, Lyle D. Isaacs, Adam R. Urbach
Chemistry Faculty Research
This paper describes the design and synthesis of a conjugate (Q7R) comprising the synthetic host cucurbit[7]uril (Q7) linked to the fluorescent dye tetramethylrhodamine (TMR), and the characterization of its optical and guest-binding properties as well as its cellular uptake. Q7R was synthesized in two steps from monofunctionalized azidobutyl-Q7 and NHS-activated TMR. The fluorescence of Q7R is quenched upon guest binding, and this observable was used to determine equilibrium dissociation constant (Kd) values. Unexpectedly, the Kd values for guests binding to Q7R and to unmodified Q7 were essentially identical. Therefore, Q7R can directly report binding to Q7 without …
Sequence-Specific, Nanomolar Peptide Binding Via Cucurbit[8]Uril-Induced Folding And Inclusion Of Neighboring Side Chains, Lauren C. Smith, David G. Leach, Brittney E. Blaylock, Omar A. Ali, Adam R. Urbach
Sequence-Specific, Nanomolar Peptide Binding Via Cucurbit[8]Uril-Induced Folding And Inclusion Of Neighboring Side Chains, Lauren C. Smith, David G. Leach, Brittney E. Blaylock, Omar A. Ali, Adam R. Urbach
Chemistry Faculty Research
This paper describes the molecular recognition of the tripeptide Tyr-Leu-Ala by the synthetic receptor cucurbit[8]uril (Q8) in aqueous buffer with nanomolar affinity and exceptional specificity. This combination of characteristics, which also applies to antibodies, is desirable for applications in biochemistry and biotechnology but has eluded supramolecular chemists for decades. Building on prior knowledge that Q8 binds to peptides with N-terminal aromatic residues, a library screen of 105 peptides was designed to test the effects of residues adjacent to N-terminal Trp, Phe, or Tyr. The screen used tetramethylbenzobis(imidazolium) (MBBI) as a fluorescent indicator and resulted in the unexpected discovery that MBBI …
Acyl-Chain Mismatch Driven Superlattice Arrangements In Dppc/Dlpc/Cholesterol Bilayers, Brian Cannon, Anthony Lewis, Pentti Somerharju, Jorma Virtanen, Juyang Huang, Kwan H. Cheng
Acyl-Chain Mismatch Driven Superlattice Arrangements In Dppc/Dlpc/Cholesterol Bilayers, Brian Cannon, Anthony Lewis, Pentti Somerharju, Jorma Virtanen, Juyang Huang, Kwan H. Cheng
Physics and Astronomy Faculty Research
Fluorescence and infrared spectroscopy and cholesterol oxidase activity were employed to investigate the effect of phosphatidylcholine (PC) acyl chain length mismatch on the lateral organizations of lipids in liquid-ordered dipalmitoyl-PC/dilauroyl-PC/cholesterol (DPPC/DLPC/CHOL) bilayers. Plots of steady-state fluorescence emission anisotropy of diphenylhexatriene (DPH) labeled PC (DPH-PC) embedded in the DPPC/DLPC/CHOL bilayers revealed significant peaks at several DPPC mole fractions (YDPPC) when the cholesterol mole fraction (XCHOL) was fixed to particular values. Analogously, the DPH-PC anisotropy peaked at several critical XCHOL’s when YDPPC was fixed. Acyl chain C−H and C═O vibrational peak frequencies of …
Ultrafast Optical Study Of Small Gold Monolayer Protected Clusters: A Closer Look At Emission, S. Hei Yau, O. Varnavski, John D. Gilbertson, Bert D. Chandler, G. Ramakrishna, T. Goodson
Ultrafast Optical Study Of Small Gold Monolayer Protected Clusters: A Closer Look At Emission, S. Hei Yau, O. Varnavski, John D. Gilbertson, Bert D. Chandler, G. Ramakrishna, T. Goodson
Chemistry Faculty Research
Monolayer-protected metal nanoclusters (MPCs) were investigated to probe their fundamental excitation and emission properties. In particular, gold MPCs were probed by steady-state and time-resolved spectroscopic measurements; the results were used to examine the mechanism of emission in relation to the excited states in these systems. In steady-state measurements, the photoluminescence of gold clusters in the range of 25 to 140 atoms was considerably stronger relative to larger particle analogues. The increase in emission efficiency (for Au25, Au55, and Au140 on the order of 10-5) over bulk gold may arise from a different mechanism …
Patterning High Surface Area Silica With Lysozyme: Adsorption Kinetics, Fluorescence Quenching, And Protein Readsorption Studies To Evaluate The Templated Surface, Rachel M. Greer, Brittni A. Scruggs, R Alan May, Bert D. Chandler
Patterning High Surface Area Silica With Lysozyme: Adsorption Kinetics, Fluorescence Quenching, And Protein Readsorption Studies To Evaluate The Templated Surface, Rachel M. Greer, Brittni A. Scruggs, R Alan May, Bert D. Chandler
Chemistry Faculty Research
A method was developed for using an inexpensive and widely available protein, hen egg white lysozyme, as a patterning agent for commercial high surface area silicas. The basic patterning methodology involved spontaneous adsorption of the protein from aqueous solution, alkylation of the uncovered surface with an alkylsiloxane, and protein desorption in a slightly alkaline solution of morpholine. Adsorption kinetic studies using Bradford assays assisted in determining protein deposition conditions. These studies were generally consistent with results on more planar silica surfaces and indicated that the protein quickly and strongly adsorbs along its long axis at low surface coverages. A modified …
Charge-Mediated Recognition Of N-Terminal Tryptophan In Aqueous Solution By A Synthetic Host, Meghan E. Bush, Nicole D. Bouley, Adam R. Urbach
Charge-Mediated Recognition Of N-Terminal Tryptophan In Aqueous Solution By A Synthetic Host, Meghan E. Bush, Nicole D. Bouley, Adam R. Urbach
Chemistry Faculty Research
The molecular recognition of peptides and proteins in aqueous solution by designed molecules remains an elusive goal with broad implications for basic biochemical research and for sensors and separations technologies. This paper describes the recognition of N-terminal tryptophan in aqueous solution by the synthetic host cucurbit[8]uril (Q8). Q8 is known to form 1:1:1 heteroternary complexes with methyl viologen (MV) and a second aromatic guest. Here, the complexes of Q8·MV with (i) the four natural aromatic α-amino acids, (ii) four singly charged tryptophan derivatives, and (iii) four tryptophan-containing tripeptides were characterized by isothermal titration calorimetry, mass spectrometry, and UV−visible, fluorescence, and …