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Extracellular vesicle integrins act as a nexus for platelet adhesion in cerebral microvessels.
Circulating extracellular vesicles (EVs) regulate signaling pathways via receptor-ligand interactions and content delivery, after attachment or internalization by endothelial cells. However, they originate from diverse cell populations and are heterogeneous in composition. To determine the effects of specific surfa…
In vivo behaviour of glyco-NaI@SWCNT ‘nanobottles’
Carbon nanotubes are appealing imaging and therapeutic systems. Their structure allows not only a useful display of molecules on their outer surface but at the same time the protection of encapsulated cargoes. Despite the interest they have provoked in the scientific community, their applications have not yet…
Strategies in the Design and Use of Synthetic "Internal Glycan" Vaccines.
The relative structural conservation of "internal glycans" in the cell walls of pathogens suggests that they might as target epitopes less prone to variation and hence with greater potential universality as vaccine targets. Examples of such glycans include the inner core sugars of lipopolysaccharides in Gram-negativ…
Most human proteins made in both nucleus and cytoplasm turn over within minutes.
In bacteria, protein synthesis can be coupled to transcription, but in eukaryotes it is believed to occur solely in the cytoplasm. Using pulses as short as 5 s, we find that three analogues--L-azidohomoalanine, puromycin (detected after attaching fluors using 'click' chemistry or immuno-labeling), and amino acids tag…
Virus-like glycodendrinanoparticles displaying quasi-equivalent nested polyvalency upon glycoprotein platforms potently block viral infection.
Ligand polyvalency is a powerful modulator of protein-receptor interactions. Host-pathogen infection interactions are often mediated by glycan ligand-protein interactions, yet its interrogation with very high copy number ligands has been limited to heterogenous systems. Here we report that through the use of ne…
High-purity discrete PEG-oligomer crystals allow structural insight.
To great (monodisperse) lengths: An improved synthesis of purer ethylene glycol (EG) oligomers allows access to 16- and 32-mers pure enough for multiple incorporation, and also to the longest (48-mer) discrete EG oligomer yet reported. The high purity enables the first crystallizations and hence the first glimp…
The linear assembly of a pure glycoenzyme.
A labor of love: The synthesis of an active pure enzyme (RNase) glycoform by the native chemical ligation of a (glyco)peptide and peptide thioester fragments required numerous painstaking steps: the strategy was optimized, active inteins accessed, redox conditions fine-tuned, and glycoamino acid buil…
Core-shell PbI2@WS2 inorganic nanotubes from capillary wetting.
Multiwall WS(2) nanotube templates were used as hosts to prepare core-shell PbI(2)@WS(2) nanotubes by a capillary-wetting method. Conformal growth of PbI(2) layers on the inner wall of the relatively wide WS(2) nanotubes (i.d. ca. 10 nm) leads to nanotubular structures which were not previously observed in…
Conformational choice and selectivity in singly and multiply hydrated monosaccharides in the gas phase.
Factors governing hydration, regioselectivity and conformational choice in hydrated carbohydrates have been examined by determining and reviewing the structures of a systematically varied set of singly and multiply hydrated monosaccharide complexes in the gas phase. This has been achieved through a co…
Site-selective glycosylation of proteins: creating synthetic glycoproteins.
In higher organisms, the functions of many proteins are modulated by post-translational modifications (PTMs). Glycosylation is by far the most diverse of the PTM processes. Natural protein production methods typically produce PTM or glycoform mixtures within which function is difficult to dissect or control. Che…
Functional and informatics analysis enables glycosyltransferase activity prediction.
The elucidation and prediction of how changes in a protein result in altered activities and selectivities remain a major challenge in chemistry. Two hurdles have prevented accurate family-wide models: obtaining (i) diverse datasets and (ii) suitable parameter frameworks that encapsulate activities in large sets.…
Lectin-directed enzyme activated prodrug therapy (LEAPT): Synthesis and evaluation of rhamnose-capped prodrugs.
The lectin-directed enzyme activated prodrug therapy (LEAPT) bipartite drug delivery system utilizes glycosylated enzyme, localized according to its sugar pattern, and capped prodrugs released by that enzyme. In this way, the sugar coat of a synthetic enzyme determines the site of release of a given drug. He…
Chemical mutagenesis: selective post-expression interconversion of protein amino acid residues.
The ability to alter protein structure by site-directed mutagenesis has revolutionized biochemical research. Controlled mutations at the DNA level, before protein translation, are now routine. These techniques allow specific, high fidelity interconversion largely between 20 natural, proteinogenic amino acids. N…