ABSTRACT
Sialosides containing C8-modified sialic acids are challenging synthetic targets but potentially useful probes for diagnostic substrate profiling of sialidases and elucidating the binding specificity of sialic acid-interacting proteins. Here, we demonstrate efficient chemoenzymatic methods for synthesizing para-nitrophenol-tagged α2-3- and α2-6-linked sialyl galactosides containing C8-acetamido, C8-azido, or C8-amino derivatized N-acetylneuraminic acid (Neu5Ac). High-throughput substrate specificity studies showed that the C8-modification of sialic acid significantly changes its recognition by sialidases from humans, various bacteria, and different influenza A and B viruses. Sialosides carrying Neu5Ac with a C8-azido modification were generally well tolerated by all the sialidases we tested, whereas sialosides containing C8-acetamido-modified Neu5Ac were only cleaved by selective bacterial sialidases. In contrast, sialosides with C8-amino-modified Neu5Ac were cleaved by a combination of selective bacterial and influenza A virus sialidases. These results indicate that sialosides terminated with a C8-amino or C8-acetamido-modified sialic acid can be used with other sialosides for diagnostic profiling of disease-causing sialidase-producing pathogens.
Subject(s)
Neuraminidase , Sialic Acids , Neuraminidase/metabolism , Substrate Specificity , Humans , Sialic Acids/chemistry , Sialic Acids/metabolism , N-Acetylneuraminic Acid/chemistry , N-Acetylneuraminic Acid/metabolism , Bacteria/enzymology , Orthomyxoviridae/enzymology , Influenza A virus/enzymologyABSTRACT
Influenza viruses contribute significantly to the global health burden, necessitating the development of strategies against transmission as well as effective antiviral treatments. The present study reports a biomimetic strategy inspired by the natural antiviral properties of mucins. A bovine serum albumin (BSA) conjugate decorated with the multivalent neuraminidase inhibitor Zanamivir (ZA-BSA) was synthesized using copper-free click chemistry. This synthetic pseudo-mucin exhibited potent neuraminidase inhibitory activity against several influenza strains. Virus capture and growth inhibition assays demonstrated its effective absorption of virion particles and ability to prevent viral infection in nanomolar concentrations. Investigation of the underlying antiviral mechanism of ZA-BSA revealed a dual mode of action, involving disruption of the initial stages of host-cell binding and fusion by inducing viral aggregation, followed by blocking the release of newly assembled virions by targeting neuraminidase activity. Notably, the conjugate also exhibited potent inhibitory activity against Oseltamivir-resistant neuraminidase variant comparable to the monomeric Zanamivir. These findings highlight the application of multivalent drug presentation on protein scaffold to mimic mucin adsorption of viruses, together with counteracting drug resistance. This innovative approach has potential for the creation of antiviral agents against influenza and other viral infections.
Subject(s)
Antiviral Agents , Mucins , Neuraminidase , Virion , Zanamivir , Neuraminidase/antagonists & inhibitors , Neuraminidase/metabolism , Zanamivir/pharmacology , Zanamivir/chemistry , Antiviral Agents/pharmacology , Antiviral Agents/chemistry , Mucins/metabolism , Mucins/chemistry , Humans , Virion/drug effects , Animals , Serum Albumin, Bovine/chemistry , Dogs , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/chemistry , Madin Darby Canine Kidney Cells , Orthomyxoviridae/drug effects , Orthomyxoviridae/enzymologyABSTRACT
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