| Proteins and nucleic acids are important biomolecules of life science and biochemistry. Proteins are the carrier of many physiological functions, and are also the direct expressers of physiological characters. Nucleic acids are primary materials showing the heredity and variation of life. To further investigate the interaction mechanism between small molecules and proteins or nucleic acids, it is very important for researchers to expound the essence of life phenomena. Molecular recognition based on fluorescence detection has many merits such as high sensitivity, high selectivity and easy operation. It has attracted much attention and has been applied to biochemistry. In this thesis, 2, 5-di-[2-(4-hydroxy-phenyl) ethylene] pyrazine and its derivatives were synthesized. Their spectra properties and application in molecular recognition of biochemistry have been investigated in the following five chapters.In chapter 1, the development of molecular recognition and main fluorescence mechanisms of recognition were reviewed.In chapter 2, the interaction between 2, 5-di-[2-(4-hydroxy-phenyl) ethylene] pyrazine (DHPEP) and serum albumins was investigated by absorption spectroscopy and fluorescence spectroscopy. FRET studies indicated the energy transfer from the proteins to the host, which made the fluorescence of the host increase and the fluorescence of the protein decrease. Synchronous fluorescence spectroscopy revealed that the secondary structure of human serum albumin (HSA) or bovine serum albumin (BSA) not changed in the presence of the host. The interaction between the host and the protein was hydrogen binding.In chapter 3, the interaction between 2,5-di-[2-(3,5-bis(2-pyridylmethyl)amine -4-hydroxy-phenyl) ethylene] pyrazine (DHPEPDPA) and serum albumin was investigated by absorption spectroscopy and fluorescence spectroscopy. Excitation wavelength and emission wavelength of host are 435 nm and 580 nm locating in visible light area in the presence of Tris-HCl buffer of pH 7.4, which shows that it is a good probe for biological system. FRET studies indicated the energy transfer from proteins to the host, which made the fluorescence of the host increase and that of proteins decrease. Synchronous fluorescence spectroscopy revealed that the secondary structure of HSA or BSA molecules was not changed in the presence of the host. The interaction between the host and the protein may happen in DPA recognise side.In chapter 4, absorption spectroscopy and fluorescence spectroscopy were used to investigate the interaction between serum albumins and 2,5-di-[2-(3,5- bis(2-Pyridyl-methyl) amine-4-hydroxy-phenyl) ethylene] pyrazine zinc complex (DHPEPDPA-Zn).Excitation wavelength and emission wavelength of the host are 435 nm and 580 nm locating in visible light area in the presence of Tris-HCl buffer of pH 7.4. Both DHPEPDPA and its zinc complex are good probes for biological system. Especially DHPEPDPA can emit strong green light when excited, which can be observed by naked eyes. DHPEPDPA-Zn has strong interaction with the protein indicated by the parameters like quenching constants, binding constants, energy transfer and the distance between the donor's fluorophore and the acceptor's fluorophore. Moreover, synchronous fluorescence spectroscopy revealed that the secondary structure of HSA or BSA molecules was also changed in the presence of the host.In chapter 5, absorption spectroscopy and fluorescence spectroscopy were used to investigate the interaction between DNA and 2,5-di-[2-(3,5-bis(2-pyridylmethyl)amine-4-hydroxy-phenyl) ethylene] pyrazine zinc complex (DHPEPDPA-Zn). The interactions between the host and DNA, denatured DNA, or RNA were studied in the presence of Tris-HCl buffer of pH 7.4. Absorption spectral change and polarization changes in the presence and absence of DNA revealed that the interaction between the probe and DNA was via intercalation. The fluorescence enhancement of the probe along with the remarkable blue shift of the maximum emission wavelength of the host was ascribed to the highly hydrophobic environment. The result indicated that the interaction between the host and DNA was electrostatic interaction besides the intercalation. The host was highly sensitive to DNA with the detection limit of 1.93×10-8 mol·L-1 for ct-DNA. The solution emitted green fluorescence and was easily detected via naked eyes. Thus the host is an ideal fluorescent probe.
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