Dual‐Locking the SARS‐CoV‐2 Spike Trimer: An Amphipathic Molecular “Bolt” Stabilizes Conserved Druggable Interfaces for Coronavirus Inhibition

Advanced Science, Год журнала: 2025, Номер unknown

Опубликована: Апрель 26, 2025

Abstract The SARS‐CoV‐2 spike (S) protein, a trimeric structure comprising three receptor binding domains (RBDs) and N‐terminal (NTDs), undergoes substantial conformational changes to fusion‐prone open state for angiotensin‐converting enzyme 2 (ACE2) host cell infection. Stabilizing its closed is key antiviral strategy but remains challenging. Here, we introduce S416, novel amphipathic molecule acting as “molecular bolt”. Cryo‐EM study reveals that S416 binds concurrently six sites across two distinct druggable interfaces: molecules at the RBD‐RBD interfaces NTD‐RBD interfaces. This unique “dual‐locking” mechanism, driven by S416's polar carboxyl head nonpolar phenylthiazole tail, robustly stabilizes trimer in locked, conformation through strong inter‐domain interactions, reducing structural flexibility atomic fluctuations compared apo resolved synchronously. Crucially, these are conserved human‐infecting coronaviruses, suggesting potential broad‐spectrum targets. Our findings demonstrate highly dynamic can be effectively stabilized an molecular bolt targeting both inter‐ intra‐monomer interfaces, offering promising against emerging coronaviruses.

Язык: Английский

Systematic Comparison of Commercial Uranyl‐Alternative Stains for Negative‐ and Positive‐Staining Transmission Electron Microscopy of Organic Specimens

Advanced Healthcare Materials, Год журнала: 2025, Номер unknown

Опубликована: Апрель 29, 2025

Abstract Negative‐ and positive‐staining transmission electron microscopy (ns/psTEM) is a cornerstone of research diagnostics, enabling nanometer‐resolution analysis organic specimens from nanoparticles to cells without requiring costly cryo‐equipment. For nearly 70 years, uranyl salts like acetate (UA) have been the gold‐standard ns/psTEM‐stains. However, mounting safety concerns due their high toxicity radioactivity led stricter regulations expensive licensing requirements. Consequently, there an urgent global demand for safer, more sustainable stains that deliver uranyl‐comparable, high‐quality ns/psTEM. Here, commercially available stain‐alternatives UranyLess, UAR, UA‐Zero, PTA, STAIN 77, Nano‐W, NanoVan, lead citrate are systematically assessed against UA. The evaluated regarding contrast, resolution, stain‐distribution, ease‐of‐use in ns/psTEM across diverse sample set, including polymethylmethacrylate‐nanoplastics, phosphatidylcholine‐liposomes, Influenza‐A viruses, globular ferritin, fibrillar pyruvate kinase amyloids, human lung‐carcinoma cell‐sections. It shown this variety samples, ready‐to‐use uranyl‐alternative with comparable or even superior ns/psTEM‐performance UA using efficient staining‐protocol. Furthermore, GUIDE4U tool developed fast identification appropriate uranyl‐replacements each interest, saving ns/psTEM‐users time costs while ensuring excellent staining results ultrastructural analysis, thereby further catalyzing use safer stains.

Язык: Английский