Detailed Molecular Interactions between Respiratory Syncytial Virus Fusion Protein and the TLR4/MD-2 Complex In Silico
Mao Akagawa, Tatsuya Shirai, Mitsuru Sada, Norika Nagasawa, Mayumi Kondo, Makoto Takeda, Koo Nagasawa, Ryusuke Kimura, Kaori Okayama, Yuriko Hayashi, Toshiyuki Sugai, Takeshi Tsugawa, Haruyuki Ishii, Hisashi Kawashima, Kazuhiko Katayama, Akihide Ryo, Hirokazu Kimura
Abstract
Molecular interactions between respiratory syncytial virus (RSV) fusion protein (F protein) and the cellular receptor Toll-like receptor 4 (TLR4) and myeloid differentiation factor-2 (MD-2) protein complex are unknown. Thus, to reveal the detailed molecular interactions between them, in silico analyses were performed using various bioinformatics techniques. The present simulation data showed that the neutralizing antibody (NT-Ab) binding sites in both prefusion and postfusion proteins at sites II and IV were involved in the interactions between them and the TLR4 molecule. Moreover, the binding affinity between postfusion proteins and the TLR4/MD-2 complex was higher than that between prefusion proteins and the TLR4/MD-2 complex. This increased binding affinity due to conformational changes in the F protein may be able to form syncytium in RSV-infected cells. These results may contribute to better understand the infectivity and pathogenicity (syncytium formation) of RSV.