Abstract
Human S100A4 protein belongs to S100 protein family which shares structure similarities with each other: they all have 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 ( EGF ) 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. In this thesis, we study the interaction between S100A4 and EGF, and we’d like to understand the complex’s characteristics. In order to meet the conditions of S100A4 NMR buffer, we dissolved EGF protein in PH6.0 solution. Using 3D NMR experiments and software calculation, we solved the structure of EGF. The binding region was characterized using 1H-15N HSQC perturbation experiments. Furthermore, we determined the binding ratio ( 1:1 ) and dissociation constant ( ~μM range ) by ITC and Fluorescent. Further studies would be necessary to characterize this interaction in more detail and to investigate if this interaction is physiologically relevant.