In Silico Modeling of Structural Compatibility and Alignment Between Viral Class I Fusion Cores and Human TLR4/MD-2.

Area of Science:

• Infectious Diseases
• Immunology
• Structural Biology
• Computational Biology

Background:

• The SARS-CoV-2 spike protein's interaction with Toll-like receptor 4 (TLR4) is known to activate innate immunity.
• The specific molecular details of this spike protein-TLR4 recognition and activation remain largely undefined.
• Understanding these interactions is crucial for deciphering viral pathogenesis and host immune responses.

Purpose of the Study:

• To computationally investigate the structural basis of SARS-CoV-2 spike protein recognition by human TLR4/MD-2.
• To identify potential molecular interfaces and interaction types involved in this binding event.
• To explore conserved structural compatibilities with fusion proteins from other pathogenic viruses.

Main Methods:

• In silico structural alignments of viral fusion cores and human TLR4/MD-2 heterodimers.
• Molecular docking simulations to predict binding modes and interfaces.
• Analysis of potential intermolecular interactions, including salt bridges, polar, and non-polar contacts.

Main Results:

• Computational models suggest spatial compatibility between the SARS-CoV-2 HR1HR2 fusion core and the TLR4/MD-2 complex.
• Predicted interfaces involve interactions with both TLR4 and MD-2, supporting a model of TLR4/MD-2 complex dimerization.
• Similar structural compatibility was observed for fusion proteins from SARS-CoV, MERS-CoV, influenza, RSV, and Ebola viruses.

Conclusions:

• These findings provide a computational hypothesis for how viral fusion proteins interact with TLR4/MD-2.
• The proposed mechanism offers insight into viral immune system activation, potentially leading to immune recognition or hyperactivation.
• The conserved structural compatibility highlights a potential common pathway for innate immune activation by diverse viral pathogens.