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Showing 1 to 20 of 35 for “"Unnatural amino acid"”.
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Development Of Unnatural Amino Acid Based Spectroscopic Probes For Chemical And Biological Applications
… spectroscopic signals arising from natural amino acids often lack site specificity, due to spectral overlapping, degeneracy, and coupling, or insensitivity to environmental changes. To overcome this limitation, a common practice is to introduce one or multiple external spectroscopic probes …
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Electrochemical Detection of Anti-Biofilm Activity Using Unnatural Amino Acid-Containing Antimicrobial Peptides
… of antimicrobial peptides (AMP) containing unnatural Tic-Oic amino acids have been developed for this purpose. Traditional methods such as biological assays are the standard by which antibiotics are judged, but they have their drawbacks, such as the lengthy test times and the costs …
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The Ribosome Discriminates the Structure of the Amino Acid at its Peptidyl-Transferase Center
… original Adaptor Hypothesis view both the amino acid and the tRNA body as passive participants during aminoacyl-tRNA (aa-tRNA) selection by the ribosome. Recent experimental evidence investigating tRNA mutants that miscode due to mutations that lie outside the anticodon as well as data from …
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Exploring the Roles of Heme Type and Histidine -Tyrosine Cross -Link in Heme-Copper Oxidases Using a Myoglobin Model
… in HCO to the model by direct incorporation of unnatural amino acid(s) into the protein sequence. These strategies demonstrate the power of combining the strength of biological, chemical and modern analytical techniques to create accurate biosynthesis models of protein active sites which can …
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Metalloprotein engineering with unnatural amino acids: application in functional heme-copper oxidase and azurin
… provides us the ability to mutate certain amino acid in metalloproteins to all other natural amino acids through site-directed mutagenesis. However, site-directed mutagenesis is restricted to 20 natural amino acids, only half of which could coordinate to metal. Incorporation of unnatural …
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From Probes to Cell Surface Labelling: Towards the Development of New Chemical Biology Compounds and Methods
… chemistry, often by virtue of small molecules or unnatural amino acids. Much insight has been gained into the mechanisms of biological processes with regards to protein structure and function, metabolic processes and changes between healthy and diseased states. As an ever expanding field, …
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The asymmetric synthesis of (2S,3R)-capreomycidine and the total synthesis of capreomycin IB
… asymmetric synthesis of the non-proteinogenic amino acid (2S,3R)-capreomycidine is presented. The synthesis features a novel aluminum enolate-aldimine reaction with a chiral glycinate, which sets both stereocenters. A concise and high-yielding approach to the unnatural amino acid …
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Investigating and expanding the functionality of RNA catalysts: Studies of the hepatitis delta virus, the hammerhead, and the aminoacyl-tRNA synthetase-like ribozymes
… ribozyme that mimics the function of the natural aminoacyl-tRNA synthetase. The design was based on the sequence of a naturally occurring riboswitch and an in vitro selected ribozyme that could charge tRNA with chemically synthesized unnatural amino acid substrates. The engineered ribozyme …
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Synthesis and enzymatic resolution of amino acid esters in "green" solvents -- ionic liquids
… in the area of chiral drug development. Chiral amino acids are among the most important intermediates in the asymmetric synthesis of modem drugs. This research has developed an effective method for obtaining optically pure amino acids by enzymatic resolution using a "green" solvent, named an …
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Synthesis of Novel Chiral Heterocyclic Compounds for Antibacterial Agents and Peptidomimetics
… ring; this Choi moiety is a rigid bicyclic unnatural amino acid and is the core structure in the aeruginosins, indispensable to their biological activity. A synthesis of a ring-oxygenated variant of the Choi from D-mannose is reported in this dissertation. The ring-oxygenated variant of …
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Synthesis and dye leakage assay of human and rat islet amyloid polypeptide 10-19 and insulin 14-18
… the active site of insulin was replaced with an unnatural amino acid (n-methyl tyrosine) but synthesis failed repeatedly. The ability of hIAPP 10-19 to disrupt membranes was tested using a dye leakage assay. The fluorescence of the peptide was measured in increasing concentrations to determine …
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Towards The Development Of Intrinsically Fluorescent Unnatural Amino Acids For In Vivo Incorporation Into Proteins
Acridonylalanine (Acd) is a fluorescent unnatural amino acid that can site specifically label a protein of interest during protein translation. Acd’s incorporation relies on an evolved tRNA synthetase that specifically charges Acd to its cognate tRNA. As the protein mRNA sequence is being …
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Expanding the genetic code of a mouse
… has used the site-specific insertion of unnatural amino acids into proteins(Greiss and Chin, 2011). An aminoacyl-tRNA synthetase and a tRNA are used to specifically insert the unnatural amino acid during mRNA translation, in response to an amber stop codon (UAG) placed at a user-defined …
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Mechanistic investigations of the radical initiation pathway of class I ribonucleotide reductase from Escherichia coli
… A. This pathway is thought to involve specific amino acid radical intermediates (Y22-> W48-> Y356 within R2 to Y731-> Y730-> C439 within R1). In an effort to study radical initiation, we used intein technology to semi-synthetically synthesize R2 (375 residues) where Y356 is replaced with an …
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Chemical Tools for Exploring IFITM3 S-Palmitoylation and Mechanism
… for site-specific IFITM3 labeling with unnatural amino acids for bioorthogonal imaging and covalent protein crosslinking in mammalian cells in Chapter 3. Using the pyrrolysyl-tRNA synthetase (PylRS)/Pyl tRNACUA system, I showed that unnatural amino acid can be site-specifically …
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The Identification and Pharmacological Characterisation of Novel Apelin Receptor Agonists In Vitro and In Vivo
… disease. An apelin mimetic peptide possessing an unnatural amino acid, MM202, conjugated chemically via a polyethylene glycol linker to an anti-serum domain antibody (AlbudAb) was also characterised. The product MM202-AlbudAb represents the first time an AlbudAb has been conjugated chemically to …
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Biochemical mechanisms for selectivity governing RNA and DNA replication
… by site specifically incorporating a fluorescent unnatural amino acid into the enzyme at a position that gives a fluorescence signal upon nucleotide binding. In addition, I developed high throughput methods to analyze kinetic samples by capillary electrophoresis to assist in the kinetic analysis …
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Transcription Coupled DNA Repair in Saccharomyces Cerevisiae: the Interplay of Facilitators and Repressors
… By site-specific incorporation of the unnatural amino acid p-benzoyl-L-phenylalanine, we mapped interactions between Spt5 and RNAP II in S. cerevisiae. Through its KOW4-5 domains, Spt5 extensively interacts with Rpb4/7. Spt5 also interacts with Rpb1 and Rpb2, two largest subunits of …
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Programmable Assembly of Elastin-like Polypeptides Within Droplet Microenvironments
… various cellular processes such as ribonucleic acid maintenance and gene expression. While the physicochemical drivers and biophysical properties of intracellular organelles is becoming clear, their functions remain poorly understood due to the difficulty in probing them and the lack of …
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Mechanistic studies of the radical transport pathway in aminotyrosine-substituted class Ia ribonucleotide reductase
… (PCET) events through redox-active aromatic amino acid residues: Y₁₂₂* <--> [W₄₈] <--> Y₃₅₆ in [beta]2 to Y₇₃₁ <--> Y₇₃₀ <--> C₄₃₉ in [alpha]2. Once formed, the transient C₄₃₉* initiates nucleotide reduction. Both the long-range oxidation and the nucleotide reduction chemistries are …
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