Evidence for ProTα-TLR4/MD-2 binding: molecular dynamics and gravimetric assay studies. (July 2015)

• Record Type: Journal Article
• Authors: Omotuyi, Olaposi; Matsunaga, Hayato; Ueda, Hiroshi
• Is Part Of: Expert opinion on biological therapy. Volume 15:Number 1(2015:Jan.)
• Page Start: 223
• Page End: 229
• Publication Date: 2015-07
• Subjects: Gene therapy -- Periodicals; Protein drugs -- Periodicals; Peptide drugs -- Periodicals; Immunotherapy -- Periodicals; Drug delivery systems -- Periodicals; 615.5
• DOI: 10.1517/14712598.2015.1005597
• Languages: English
• ISSNs: 1471-2598

Abstract

<abstract> <title> <x xml:space="preserve">Abstract</x> </title> <p> <bold> <italic>Objective:</italic> </bold> During preconditioning, lipopolysaccharide (LPS) selectively activates TLR4/MD-2/Toll/IL-1 receptor-domain-containing adaptor inducing IFN-β (TRIF) pathway instead of pro-inflammatory myeloid differentiation protein-88 (MyD88)/MyD88-adaptor-like protein (MAL) pathway. Extracellular prothymosin alpha (ProTα) is also known to selectively activate the TLR4/MD2/TRIF–IRF3 pathway in certain diseased conditions. In the current study, biophysical evidence for ProTα/TLR4/MD-2 complex formation and its interaction dynamics have been studied.</p> <p> <bold> <italic>Research design and methods:</italic> </bold> Gravimetric assay was used to investigate ProTα/TLR4/MD-2 complex formation while molecular dynamics (MD) simulation was used to study its interaction dynamics.</p> <p> <bold> <italic>Results:</italic> </bold> Through electrostatic interaction, full-length ProTα (F-ProTα) C-terminal peptide (aa 91 – 111) superficially interacts with similar TLR4/MD-2 (K<sub>D</sub> = 273.36 nm vs 16.07 μg/ml [LPS]) conformation with LPS at an overlapping three-dimensional space while F-ProTα is hinged to the TLR4 scaffold by one-amino acid shift-Mosoian domain (aa-51 – 90). Comparatively, F-ProTα better stabilizes MD-2 metastable states transition and mediates higher TLR4/MD-2 interaction than LPS.</p> <p> <bold> <italic>Conclusions: </italic> </bold>ProTα via its C-terminal peptide (aa 91 – 111) exhibits <italic>in vitro</italic> biophysical contact with TLR4/MD-2 complex conformation recognized by LPS at overlapping LPS-binding positions.</p> </abstract>