Abstract
Human S100 proteins belong to a family of small, acidic protein which shares high structure similarities with each other: they all have two EF-hand motifs and could bind calcium. When S100A4 binds with calcium, it will change its conformation and interact with their target protein. Human epidermal growth factor ( hEGF ) is the target protein which is also one of the high affinity ligands of EGFR. EGF/EGFR system promotes cell survival, growth and differentiation via the activation of several integrated signaling pathways. In recent studies, scientists used western blotting to show that S100A4 could interact with EGF. Amlexanox is an anti-inflammatory and antiallergic drug used to treat recurrent aphthous ulcers. In this study, we found AMX interact with S100A4 using HSQC titrations. We elucidated the interactions of S100A4 with EGF and AMX using fluorescence spectroscopy and NMR spectroscopy. We solved the solution complex structures and investigated the bioactivities using WST-1 assay. The results we reported could help to investigate the biological mechanism among S100A4, EGF and AMX.