Abstract: The interactions of separated and purified recombinant Chemosensory proteins 3 (CSP3) of Chinese honeybee, Apis cerana cerana with its special ligands, N-Phenyl-1-naphthylamine (1-NPN) was investigated with the method of fluorescence spectroscopy. The results showed that 1-NPN could quench the intrinsic fluorescence of CSP3 at 328 nm (λem) by static quenching and hydrophobic interaction was the predominant intermolecular force, and the binding distance (r = 9.3 nm) and energy-transfer efficiency (E = 0.054) bewteen donor (CSP3) and acceptor (1-NPN) were obtained according to the F?rster-type dipole-dipole nonradiative energy-transfer mechanism. In addition, from the results of synchronous fluorescence spectroscopy, the tryptophan residue contributed the main fluorescent emission, and with its λmax turnning to red shift, it indicated that 1-NPN can affect the the conformation of CSP3, and increase the polarity of tryptophan residue in the hydrophobic cavity of CSP3.

Key words: Apis cerana cerana, chemosensory protein, interaction, fluorescence spectroscopy