15 May 2020

Crystal structure of Nsp15 endoribonuclease NendoU from SARS-CoV-2

Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) is rapidly spreading around the world. There is no existing vaccine or proven drug to pre- vent infections and stop virus proliferation. Although this virus is similar to human and animal SARS-CoVs and Middle East Respiratory Syndrome coronavirus (MERS-CoVs), the detailed information about SARS-CoV-2 proteins structures and functions is urgently needed to rapidly develop effective vaccines, antibodies, and antivirals. Andrzej Joachimiak et. al applied high-throughput protein production and structure determination pipeline at the Center for Structural Genomics of Infectious Diseases, Argonne National Laboratory, to produce SARS-CoV-2 proteins and structures. In the Protein Science paper they report two high-resolution crystal structures of endoribonuclease Nsp15/NendoU and compare these structures with previously reported homologs from SARS and MERS coronaviruses.

5 May 2020

Structural basis for the recognition of SARS-CoV-2 by full-length human ACE2

Angiotensin-converting enzyme 2 (ACE2) is the cellular receptor for severe acute respiratory syndrome– coronavirus (SARS-CoV) and the new coronavirus (SARS-CoV-2) that is causing the serious coronavirus disease 2019 (COVID-19) epidemic. The Science article by Qiang Zhou et. al. presents cryo–electron microscopy structures of full-length human ACE2 in the presence of the neutral amino acid transporter B0AT1 with or without the receptor binding domain (RBD) of the surface spike glycoprotein (S protein) of SARS-CoV-2, both at an overall resolution of 2.9 angstroms, with a local resolution of 3.5 angstroms at the ACE2-RBD interface. The ACE2-B0AT1 complex is assembled as a dimer of heterodimers, with the collectrin-like domain of ACE2 mediating homodimerization. The RBD is recognized by the extracellular peptidase domain
of ACE2 mainly through polar residues. These findings provide important insights into the molecular basis for coronavirus recognition and infection.

5 May 2020

Crystal structure of SARS-CoV-2 main protease provides a basis for design of improved a-ketoamide inhibitors Crystal structure of SARS-CoV-2 main protease provides a basis for design of improved a-ketoamide inhibitors

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome– coronavirus 2 (SARS-CoV-2) is a global health emergency. An attractive drug target among coronaviruses is the main protease (Mpro, also called 3CLpro) because of its essential role in processing the polyproteins that are translated from the viral RNA. Rolf Hingenfeld et. al. report in Science the x-ray structures of the unliganded SARS-CoV-2 Mpro and its complex with an a-ketoamide inhibitor. This was derived from a previously designed inhibitor but with the P3-P2 amide bond incorporated into a pyridone ring to enhance the half-life of the compound in plasma. On the basis of the unliganded structure, they developed the lead compound into a potent inhibitor of the SARS-CoV-2 Mpro. The pharmacokinetic characterization of the optimized inhibitor reveals a pronounced lung tropism and suitability for administration by the inhalative route.

Principles for Integrative Structural Biology Studies

Guru of integrative structural biology computation Andrej Sali and Michale P. Rout summarize in the recent Cell Primer Principles for Integrative Structural Biology Studies.

Visualization of biological macromolecules at near-atomic resolution: cryo-electron microscopy comes of age

The topical review by Alok K. Mitra recapitulates developments and transformational advances of cryo-EM technology.

16 Jul 2019

The expanding toolkit for structural biology: synchrotrons, X-ray lasers and cryo-EM

Samar Hasnain et. al. describe the steadily-expanding methodologies for atomic resolution studies in The expanding toolkit for structural biology: synchrotrons, X-ray lasers and cryo-EM. Of note is the following statistics: Despite the wealth of structures in the Protein Data Bank, a closer examination reveals that 89% of the structures, i.e. 126 994, are of proteins or complexes with a molecular weight of less than 160 kDa. Furthermore, only 4% of the deposited structures have a molecular weight in excess of 300 kDa.