ИСТИНА

One of the major membrane glycoproteins of Influenza virus – neuraminidase – plays a key role in virus replication cycle by cleaving sialic acid from host cell surface facilitating release of virions and spread of infection. The external arrangement of neuraminidase makes it primary target for antiviral therapeutic strategies but results in permanent evolutionary pressure by a host immune system and high mutational frequency. This phenomenon leads Influenza to rapid developing of viral resistance to modern therapeutics constituting an emerging challenge in medicine. The promising inhibitor design approach relies on precise mimicking of substrate’s transition state structure during enzyme catalysis. Recent development workflow of neuraminidase inhibitors which had not produced effective candidate molecules was based on the assumption of substrate’s terminal sialic acid following 3S1-> 3H4 conformational path during catalysis revealed in experiments with p-nitrophenyl derivative but not the native oligosaccharide substrate [1]. In this work using molecular modeling we demonstrate that substrate’s p-nitrophenyl derivative undergoes alternative conformational transitions compared to native trisaccharides thus hiding true conformational requirements for transition-state mimicking inhibitors. Comparative analysis has been made on reconstructed free energy landscapes for both 3’sialolactose and p-nitrophenol α-D-sialoside bound to H5N1 Influenza neuraminidase by the molecular modelling of Michaelis complex formation using nonparametric Bayesian clustering of glycan structures coupled with metadynamics [2]. p-Nitrophenyl derivative demonstrated 25B state as a major conformation for sugar ring structure not seeing in a complex of neuraminidase with a native 3’sialolactose substrate which exhibits strong stabilization of intermediate state between 5S1 and B14 while prohibiting the majority of other possible conformations. Design of effective antivirals might benefit if takes into account geometric properties of 5S1, B14 and closest possible E4 transition state for a core structure of candidate molecules. This study was supported by the RFBR grant № 18-34-00953.