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Full-Text Articles in Physical Sciences and Mathematics
Scope Of Amino Acid Recognition By Cucurbit[8]Uril, Preetika Rajgariah, Adam Urbach
Scope Of Amino Acid Recognition By Cucurbit[8]Uril, Preetika Rajgariah, Adam Urbach
Adam R Urbach
This paper describes the molecular recognition of amino acids by cucurbit[8]uril (Q8) and by the 1:1 complex between Q8 and methyl viologen (MV) in purely aqueous solution. These hosts are known to bind aromatic peptides with high affinity and sequence specificity, but prior work has focused on only a small subset of amino acids. In an effort to elucidate the scope and limitations of amino acid recognition by Q8 and Q8•MV, a comprehensive examination of the 20 genetically encoded amino acids was carried out by 1H NMR spectroscopy and isothermal titration calorimetry. We find that both Q8 and Q8•MV …
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
Adam R Urbach
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 …
Effects Of The Number And Placement Of Positive Charges On Viologen–Cucurbit[N]Uril Interactions, Gretchen Vincil, Adam Urbach
Effects Of The Number And Placement Of Positive Charges On Viologen–Cucurbit[N]Uril Interactions, Gretchen Vincil, Adam Urbach
Adam R Urbach
Recent developments in the synthesis and applications of the cucurbit[n]uril family of synthetic hosts has led to an increasing interest in the detailed studies of their interactions with a wide variety of guests. This paper describes a quantitative study of the effects of the number and placement of positive charges on the binding of viologen guests to cucurbit[7]uril and cucurbit[8]uril. A series of viologen derivatives with one to four charges was characterised by isothermal titration calorimetry, 1H NMR spectroscopy and mass spectrometry to determine the stoichiometry, affinity and mode of binding. These data show that stoichiometry can be controlled by …
Effects Of Sequence Context On The Binding Of Tryptophan-Containing Peptides By The Cucurbit[8]Uril-Methyl Viologen Complex, Omar Ali, Eric Olson, Adam Urbach
Effects Of Sequence Context On The Binding Of Tryptophan-Containing Peptides By The Cucurbit[8]Uril-Methyl Viologen Complex, Omar Ali, Eric Olson, Adam Urbach
Adam R Urbach
This paper describes a novel assay for measuring the relative extent of peptide binding in a large parallel format and the use of this assay to explore the effects of sequence context on the binding of tryptophan (Trp)-containing peptides by the synthetic receptor comprising the noncovalent complex between cucurbit[8]uril and methyl viologen (i.e. Q8√MV). The extent of quenching of Trp fluorescence upon binding to Q8√MV was used to measure the relative extent of binding and thus the relative affinities of 104 Trp-containing peptides, in parallel, using a fluorescence plate reader. This study resulted in the remarkable observation that the identity …
Benzobis(Imidazolium)–Cucurbit[8]Uril Complexes For Binding And Sensing Aromatic Compounds In Aqueous Solution, Frank Biedermann, Urs Rauwald, Monika Cziferszky, Kyle Williams, Lauren Gann, Bi Guo, Adam Urbach, Christopher Bielawski, Oren Scherman
Benzobis(Imidazolium)–Cucurbit[8]Uril Complexes For Binding And Sensing Aromatic Compounds In Aqueous Solution, Frank Biedermann, Urs Rauwald, Monika Cziferszky, Kyle Williams, Lauren Gann, Bi Guo, Adam Urbach, Christopher Bielawski, Oren Scherman
Adam R Urbach
The utilities of benzobis(imidazolium) salts (BBIs) as stable and fluorescent components of supramolecular assemblies involving the macrocyclic host, cucurbit[8]uril (CB[8]), are described. CB[8] has the unusual ability to bind tightly and selectively to two different guests in aqueous media, typically methyl viologen (MV) as the first guest, followed by an indole, naphthalene, or catechol-containing second guest. Based on similar size, shape, and charge, tetramethyl benzobis(imidazolium) (MBBI) was identified as a potential alternative to MV that would increase the repertoire of guests for cucurbit[8]uril. Isothermal titration calorimetry (ITC) studies showed that MBBI binds to CB[8] in a 1:1 ratio with an …