Epidermal growth factor binding induces a conformational change in the external domain of its receptor.

摘要: To study the properties of extracellular epidermal growth factor (EGF) binding domain human EGF receptor, we have infected insect cells with a suitably engineered baculovirus vector containing cDNA encoding entire ectodomain parent molecule. This resulted in correctly folded, stable, 110 kd protein which possessed an affinity 200 nM. The was routinely purified milligram amounts from 1 litre cell cultures using series three standard chromatographic steps. were studied before and after addition different ligands, both circular dichroism fluorescence spectroscopic techniques. A secondary structural analysis far UV CD spectrum indicated significant proportions alpha-helix beta-sheet agreement published model receptor. ligand additions to receptor showed differences near- far-UV spectra, similar for each used, suggesting conformational between uncomplexed complexed Steady-state measurements that tryptophan residues present are buried solvent-accessible tryptophans ligands become on rotational correlation times measured by anisotropy decay receptor-ligand complexes decreased 6 2.5 ns case. may indicate perturbation environment binding. Ultracentrifugation studies no aggregation occurred addition, so this could not explain observed or fluorescence.(ABSTRACT TRUNCATED AT 250 WORDS)