ChemBioChem

Journal: ChemBioChem

Abbreviation

ChemBioChem

Publisher

Wiley

ISSN

1439-4227
1439-7633

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Publications1 - 10 of 87

Self‐Assembly of Proteinaceous Shells around Positively Charged Gold Nanomaterials Enhances Colloidal Stability in High‐Ionic‐Strength Buffers
Sasaki, Eita; Dragoman, Ryan M.; Mantri, Shiksha; et al. (2020)
ChemBioChem
The enzyme lumazine synthase (LS) has been engineered to self-assemble into hollow-shell structures that encapsulate unnatural cargo proteins through complementary electrostatic interactions. Herein, we show that a negatively supercharged LS variant can also form organic–inorganic hybrids with gold nanomaterials. Simple mixing of LS pentamers with positively charged gold nanocrystals in aqueous buffer spontaneously affords protein-shelled gold cores. The procedure works well with differently sized and shaped gold nanocrystals, and the resulting shelled complexes exhibit dramatically enhanced colloidal stability over a wide range of pH (4.0–10.0) and at high ionic strength (up to 1 m NaCl). They are even stable over days upon dilution in buffer. Self-assembly of engineered LS shells in this way offers an easy and attractive alternative to commonly used ligand-exchange methods for stabilizing inorganic nanomaterials.
Solution NMR studies of recombinant Aβ(1-42): from the presence of a micellar entity to residual β-sheet structure in the soluble species
Walti, Marielle A.; Orts, Julien; Vögeli, Beat; et al. (2015)
ChemBioChem
Probing the proteolytic stability of beta peptides containing alpha fluoro- and alpha hydroxy beta amino acids
Hook, David F.; Gessier, François; Noti, Christian; et al. (2004)
ChemBioChem
Immunological Optimization of a Generic Hydrophobic Pocket for High Affinity Hapten Binding and Diels–Alder Activity
Piatesi, Andrea; Hilvert, Donald (2004)
ChemBioChem
Antibody 1E9, which binds a tetrachloronorbornene derivative with subnanomolar affinity and catalyzes the Diels–Alder reaction between tetrachlorothiophene dioxide and N‐ethylmaleimide with high efficiency, arose from a family of highly restricted germ‐line immunoglobulins that bind diverse hydrophobic ligands. Two somatic mutations, one at position L89 in the light chain (SerL89Phe) and another at position H47 in the heavy chain (TrpH47Leu), have been postulated to be responsible for the unusually high degree of shape and chemical complementarity observed in the crystal structure of 1E9 complexed with its hapten. To test this hypothesis, the germ‐line sequence at these two positions was restored by site‐directed mutagenesis. The ensuing 160 to 3900‐fold decrease in hapten affinity and the complete loss of catalytic activity support the hypothesis that these somatic mutations substantially remodel the antibody binding pocket. Mutation of the highly conserved hydrogen‐bond donor AsnH35, which sits at the bottom of the active site and is a hallmark of this family of antibodies, is also catastrophic with respect to hapten binding and catalysis. In contrast, residues in the CDR H3 loop, which contributes a significant fraction of the hapten‐contacting protein surface, have a more subtle influence on the properties of 1E9. Interestingly, while most changes in this loop have neutral or modestly deleterious effects, replacement of MetH100b at the floor of the pocket with phenylalanine leads to a significant sevenfold increase in catalytic activity. The latter result is surprising given the unusually close fit of the parent antibody to the transition‐state analogue. Further fine‐tuning of the interactions between 1E9 and its ligands by introducing mutations outside the active site could conceivably yield substantially more active catalysts.
Folding and unfolding of two mixed alpha/beta peptides
Wang, Dongqi; Jaun, Bernhard; van Gunsteren, Wilfred F. (2009)
ChemBioChem
Biosynthetic Origin of the Antibiotic Cyclocarbamate Brabantamide A (SB-253514) in Plant-Associated Pseudomonas.
Schmidt, Yvonne; van der Voort, Menno; Crüsemann, Max; et al. (2014)
ChemBioChem
Giant vesicles: Preparations and applications
Walde, Peter; Cosentino, Katia; Engel, Helen; et al. (2010)
ChemBioChem
Total Synthesis and Biological Assessment of Benzimidazole-Based Analogues of Epothilone A
Cachoux, Frederic; Isarno, Thomas; Wartmann, Markus; et al. (2006)
ChemBioChem
Making epothilones fluoresce
Gertsch, Jürg; Feyen, Fabian; Bützberger, Alexander; et al. (2009)
ChemBioChem
A green fluorescent 12‐aza‐epothilone (azathilone) derivative has been prepared through the attachment of the 4‐nitro‐2,1,3‐benzoxadiazole (NBD) fluorophore to the 12‐nitrogen atom of the azamacrolide core structure. While less potent than natural epothilones or different N12‐acylated azathilone derivatives, NBD‐azathilone (3) promotes tubulin assembly, inhibits cancer cell proliferation in vitro and arrests the cell cycle at the G2/M transition. Most significantly, the binding of 3 to cellular microtubules (MTs) could be directly visualized by confocal fluorescence microscopy. Based on competition binding experiments with laulimalide‐stabilized MTs in vitro, the N12‐Boc substituted azathilone 1, Epo A, and NBD‐azathilone (3) all interact with the same tubulin‐binding site. Computational studies provided a structural model of the complexes between β‐tubulin and 1 or 3, respectively, in which the NBD moiety of 3 or the BOC moiety of 1 directly and specifically contribute to MT binding. Collectively, these data demonstrate that the cellular effects of 3 and, by inference, also of other azathilones are the result of their interactions with the cellular MT network.
DNA-encoded chemical libraries
Scheuermann, Jörg; Neri, Dario (2010)
ChemBioChem

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Journal: ChemBioChem

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