Room-temperature structural studies of SARS-CoV-2 protein NendoU with an X-ray free-electron laser

Modular droplet injector for sample conservation providing new structural insight for the conformational heterogeneity in the disease-associated NQO1 enzyme

“…In addition, viscous media injectors have been developed to create extremely low flow rates and reduce sample consumption significantly, though these are not fast enough to replenish crystals at MHz repetition rate XFELs. 31–34 Low flow rates for sample conservation during continuous liquid injection were also induced using an electrospinning principle with the MESH injector 35,36 at the expense of higher background when crystal slurries are probed in the electro-spun cone 37 instead of the jet due to experimental optimizations of hit rates and potential impact on crystal structures.…”

Kinetic analysis of RNA cleavage by coronavirus Nsp15 endonuclease: Evidence for acid–base catalysis and substrate-dependent metal ion activation

“…Based on recent structural studies of by serial femtosecond crystallography using an X-ray free-electron laser and cryoEM structures of free and bound enzyme, Jernigan et al propose a model in which substrate binding alternates between the two trimers in the hexamer. 63 In this reaction scheme RNA binds with high affinity to one trimer, while the other trimer is more flexible. Thus, the fast and slow reaction phases observed in single turnover reactions with oligonucleotide substrates may well reflect the differential flexibility of active sites in the Nsp15 hexamer.…”

Structure-based approaches against COVID-19

“…XFEL has been used to study a major SARS-CoV-2 protein, NendoU, which helps the virus to evade the innate immune system by cleaving antisense viral ribonucleic acid (RNA). 13 Researchers have used serial femtosecond crystallography at an XFEL to determine the room-temperature structure of NendoU, thereby highlighting its flexibility and dynamics. They also demonstrated that NendoU maintains its enzyme activity in crystal form, potentially paving the way for the development of more effective antiviral drugs that target allosteric conformational changes and are less prone to resistance.…”