Miniature β-Hairpin Mimetic by Intramolecular Hydrogen Bond and C-H···π Interactions.

Canonically, protein β-hairpin motifs are stabilized by intramolecular hydrogen bonds. Here, we attempt to develop a rational design recipe for a miniature hairpin structure stabilized by hydrogen bonding as well as C-H···π interaction and try to understand how such a stabilization effect varies with different functional groups at each terminus. Database analysis shows that the α-amino acids with an aromatic side chain will not favor that kind of C-H···π stabilized hairpin structure.

Chelated Magnesium Logic Gate Regulates Riboswitch Pseudoknot Formation.

Magnesium plays a critical role in the structure, dynamics, and function of RNA. The precise microscopic effect of chelated magnesium on RNA structure is yet to be explored. Magnesium is known to act through its diffuse cloud around RNA, through the outer sphere (water-mediated), inner sphere, and often chelated ion-mediated interactions.

Dynamic Asymmetry Exposes 2019-nCoV Prefusion Spike.

The novel coronavirus (2019-nCoV) spike protein is a smart molecular machine that instigates the entry of coronavirus to the host cell causing the COVID-19 pandemic. In this study, a symmetry-information-loaded structure-based Hamiltonian is developed using recent Cryo-EM structural data to explore the complete conformational energy landscape of the full-length prefusion spike protein. The study finds the 2019-nCoV prefusion spike to adopt a unique strategy by undertaking a dynamic conformational asymmetry that results in two prevalent asymmetric structures of spike where one or two spike heads rotate up to provide better exposure to the host-cell receptor.