- Synthesis of Multi-Protein Complexes through Charge-Directed Sequential Activation of Tyrosine Residues
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Site-selective protein-protein coupling has long been a goal of chemical biology research. In recent years, that goal has been realized to varying degrees through a number of techniques, including the use of tyrosinase-based coupling strategies. Early publications utilizing tyrosinase from Agaricus bisporus(abTYR) showed the potential to convert tyrosine residues into ortho-quinone functional groups, but this enzyme is challenging to produce recombinantly and suffers from some limitations in substrate scope. Initial screens of several tyrosinase candidates revealed that the tyrosinase from Bacillus megaterium (megaTYR) is an enzyme that possesses a broad substrate tolerance. We use the expanded substrate preference as a starting point for protein design experiments and show that single point mutants of megaTYR are capable of activating tyrosine residues in various sequence contexts. We leverage this new tool to enable the construction of protein trimers via a charge-directed sequential activation of tyrosine residues (CDSAT).
- Brauer, Daniel D.,Doudna, Jennifer A.,Francis, Matthew B.,Gleason, Jamie M.,Lobba, Marco J.,Marmelstein, Alan M.,Maza, Johnathan C.,Mogilevsky, Casey S.
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Read Online
- Biodegradable hydrogels for time-controlled release of tethered peptides or proteins
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Tethering drug substances to a gel network is an effective way of controlling the release kinetics of hydrogelbased drug delivery systems. Here, we report on in situ forming, biodegradable hydrogels that allow for the covalent attachment of peptides or proteins. Hydrogels were prepared by step-growth polymerization of branched poly(ethylene glycol). The gel strength ranged from 1075 to 2435 Pa; the degradation time varied between 24 and 120 h. Fluorescence recovery after photobleaching showed that fluorescently labeled bovine serum albumin (FITC-BSA) was successfully bound to the gel network during gel formation. Within 168 h, the mobility of the tethered molecules gradually increased due to polymer degradation. Using FITC-BSA and lysozyme as model proteins, we showed the potential of the developed hydrogels for time-controlled release. The obtained release profiles had a sigmoidal shape and matched the degradation profile very well; protein release was complete after 96 h.
- Brandl, Ferdinand,Hammer, Nadine,Blunk, Torsten,Tessmar, Joerg,Goepferich, Achim
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experimental part
p. 496 - 504
(2010/12/19)
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- Synthesis and characterization of glucosamine-bound near-infrared probes for optical imaging
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Two novel near-infrared (NIR) fluorescent probes have been synthesized by linking a carbocyanine fluorophore and glucosamine through different linkers. These probes demonstrated a high quantum yield, low cytotoxicity, reversible pH-dependent fluorescence in the physiological pH range, and a decreased aggregation tendency in aqueous solutions. In vitro NIR optical imaging studies revealed cellular uptake and strong intracellular NIR fluorescence of these two probes in four breast epithelial cell lines.
- Li, Cong,Greenwood, Tiffany R.,Bhujwalla, Zaver M.,Glunde, Kristine
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p. 3623 - 3626
(2007/10/03)
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- Fluorescence studies on nyctinasty which suggest the existence of genus-specific receptors for leaf-movement factor.
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Periodic leaf-movement of legumes is called nyctinasty and has been known since the age of Alexander the Great. We found that nyctinasty is controlled by a periodic change of the internal concentration of leaf-opening and leaf-closing substances in the plant body. Now, we have developed novel fluorescent probes (1) based on the structure of cis-p-coumaroylagmatine (3), which was isolated as a leaf-opening substance of Albizzia juribrissin Durazz. Binding experiments using probe 1 showed that Albizza plants have receptors for a leaf-opening substance in their motor cells. By using probes 1 we then found that genus-specific receptors are involved in nyctinasty.
- Nagano, Hideharu,Kato, Eisuke,Yamamura, Shosuke,Ueda, Minoru
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p. 3186 - 3192
(2007/10/03)
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- New cyanopeptide-derived low molecular weight thrombin inhibitors
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Thrombosis is the result of defective regulation of the hemostasis system. This cardiovascular disorder may lead to deep vein thrombosis, myocardial infarction, and stroke. The majority of current drug research is focused on finding inhibitors of thrombin - the global player in hemostasis. In our work, we emphasize investigation of the marine environment to yield new lead structures from marine organisms like blue-green algae (cyanobacteria). This article deals with the design, syntheses, and inhibition tests of new low molecular weight thrombin inhibitors utilizing cyanopeptides, the secondary metabolites of cyanobacteria with interesting biological activities, as new lead structures. Starting with aeruginosin 98-B (2) as a lead structure, we have developed and synthesized new, selective acting inhibitors of thrombin (RA-1001 and RA-1002), which are suitable targets for further structure-activity studies.
- Radau, Gregor,Gebel, Jana,Rauh, Daniel
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p. 372 - 380
(2007/10/03)
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- Cyanopeptide analogues: New lead structures for the design and synthesis of new thrombin inhibitors
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This contribution deals with the structure-based design and syntheses of the new serine protease inhibitors RA-1001 and RA-1002, which are analogues of the blue-green algae derived cyanopeptide aeruginosin 98-B. Both compounds inhibit thrombin with Ki values of 5.6 μM and 8.7 μM, respectively.
- Radau, Gregor,Stuerzebecher
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p. 729 - 732
(2007/10/03)
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- Synthesis of a cyanopeptide-analogue with trypsin activating properties
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An efficient synthesis of a peptidic analogue of cyanobacterial metabolites with proposed serine protease inhibitory activity has been developed. Surprisingly, one trypsin activating compound was obtained. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Radau, Gregor,Rauh, Daniel
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p. 779 - 781
(2007/10/03)
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- Synthesis of N-hydroxysuccinimide esters using polymer bound HOBT
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The preparation of the N-hydroxysuccinimide esters via reactions mediated by polymer bound 1-hydrozybenzotriazole (HOBT) is reported.
- Dendrinos, Kleanthis G.,Kalivretenos, Aristotle G.
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p. 1321 - 1324
(2007/10/03)
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- Development of Potent and Selective CCK-A Receptor Agonists from Boc-CCK-4: Tetrapeptides Containing Lys(Nε)-Amide Residues
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A series of Boc-CCK-4 derivatives represented by the general structure Boc-Trp-Lys(Nε-COR)-Asp-Phe-NH2, where R is an aromatic, heterocyclic, or aliphatic group, are potent and selective CCK-A receptor agonists.These amide-bearing compounds complement the previously described urea-based tetrapeptides (Shiosaki et al.J.Med.Chem. 1991,34,2837-2842); structure-activity studies revealed parallel as well as divergent trends between these two series.A significant correlation was observed between pancreatic binding affinity and the resonance constant R of the phenyl substituent in one particular series of derivatives.Sulfation of phenolic amides appended onto the ε-amino group of the lysine did not affect affinity for the CCK-A receptor in contrast to the 500-fold increase in binding potency observed upon sulfation of CCK-8, suggesting that the lysine appendage and the sulfated tyrosine in CCK-8, both key structural elements that impart high affinity for the CCK-A receptor, are interacting differently with the receptor.The amide-bearing tetrapeptides are full agonists relative to CCK-8 in stimulating pancreatic amylase release while being partial agonists in eliciting phosphoinositide (PI) hydrolysis.Both effects were blocked by selective CCK-A receptor antagonists
- Shiosaki, Kazumi,Lin, Chun Wel,Kopecka, Hana,Craig, Richard A.,Bianchi, Bruce R.,et al.
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p. 2007 - 2014
(2007/10/02)
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