Computational insights into TLR4/MD2 interactions with dengue NS1 proteins: Serotype-specific binding and immune response

Dengue is an arthropod-borne viral disease caused by four distinct dengue virus (DENV) serotypes. The nonstructural protein-1 (NS1) plays a critical role in viral replication and modulation of host immune responses through Toll-like receptor 4 (TLR4) and its co-receptor myeloid differentiation factor 2 (MD2). Despite its importance, the molecular interactions between NS1 and the TLR4/MD2 receptor complex remain incompletely characterized. In this study, molecular docking and molecular dynamics simulations were used to investigate NS1 interactions from DENV1 and DENV2 with TLR4/MD2. DENV1-NS1 preferentially engages MD2 through extensive hydrogen bonds and hydrophobic contacts, while DENV2-NS1 exhibits stronger interactions with TLR4, forming distinct salt bridges and polar contacts. The wing and β-ladder domains from DENV1-NS1 receptor complex were identified as key interaction hotspots, with the Asn207 glycosylation site positioned at the NS1-MD2 interface, potentially mimicking LPS binding. MM-GBSA binding energy calculations validate these findings, showing MD2 as the main stabilizing partner for DENV1-NS1 and TLR4 for DENV2-NS1. Despite ∼72 % sequence identity, serotype-specific differences in binding geometry and domain engagement were observed, suggesting divergent mechanisms of receptor modulation. These computational results highlight the NS1-TLR4/MD2 interface as a critical site for immune interaction and support the rationale for serotype-specific therapeutic strategies targeting NS1-mediated receptor engagement, while experimental validation is necessary to confirm functional outcomes.