Terahertz time-domain spectroscopy (THz-TDS) is a new technique in studying the conformational state of a molecule in recent years. In this work, we reported the first use of THz-TDS to examine the dena- turation of t...Terahertz time-domain spectroscopy (THz-TDS) is a new technique in studying the conformational state of a molecule in recent years. In this work, we reported the first use of THz-TDS to examine the dena- turation of two photosynthesis membrane proteins: CP43 and CP47. THz-TDS was proven to be useful in discriminating the different conformational states of given proteins with similar structure and in monitoring the denaturation process of proteins. Upon treatment with guanidine hydrochloride (GuHCl), a 1.8 THz peak appeared for CP47 and free chlorophyll a (Chl a). This peak was deemed to originate from the interaction between Chl a and GuHCl molecules. The Chl a molecules in CP47 interacted with GuHCl more easily than those in CP43.展开更多
The excitation energy transfer efficiency between p-Car and Chla molecules in purified CP43 and CP47 was calculated by comparing absorption and fluorescence excitation after normalization at 550 nm, CP43 had an energy...The excitation energy transfer efficiency between p-Car and Chla molecules in purified CP43 and CP47 was calculated by comparing absorption and fluorescence excitation after normalization at 550 nm, CP43 had an energy transfer efficiency of 29.1% while the CP47 had an energy transfer efficiency of 62.8%, proving that excitation energy was transferred between p-Car and Chla molecules in CP43 and CP47 at normal conditions. The excitation energy transfer between p-Car and Chla molecules in CP43 and CP47 may occur through the "Dexter" mechanism and the distance between these two kinds of pigments should be less than 1 nm. In addition, the results were also used to discuss the conformational relationship between p-Car and Chla molecules in CP43 and CP47.展开更多
Light and heat induced denaturation of CP47, the core antenna complex of photosystem Ⅱ purified from spinach, were investigated using absorption and circular dichroism spectra. Light caused the destruction of chlorop...Light and heat induced denaturation of CP47, the core antenna complex of photosystem Ⅱ purified from spinach, were investigated using absorption and circular dichroism spectra. Light caused the destruction of chlorophyll a and excitonic interaction of chlorophyll a in CP47, while the protein secondary structure was not apparently changed. Heat induced the destruction of protein secondary structure and excitonic interaction of chlorophyll a, but the chlorophyll a molecule was not damaged. The results suggest that both the chlorophyll a molecular structure and the protein native conformation are necessary for excitonic interaction of chlorophyll a and the energy transfer function of the chlorophyll a binding protein.展开更多
基金the National Natural Science Foundation of China (Grant No. 39890390)
文摘Terahertz time-domain spectroscopy (THz-TDS) is a new technique in studying the conformational state of a molecule in recent years. In this work, we reported the first use of THz-TDS to examine the dena- turation of two photosynthesis membrane proteins: CP43 and CP47. THz-TDS was proven to be useful in discriminating the different conformational states of given proteins with similar structure and in monitoring the denaturation process of proteins. Upon treatment with guanidine hydrochloride (GuHCl), a 1.8 THz peak appeared for CP47 and free chlorophyll a (Chl a). This peak was deemed to originate from the interaction between Chl a and GuHCl molecules. The Chl a molecules in CP47 interacted with GuHCl more easily than those in CP43.
文摘The excitation energy transfer efficiency between p-Car and Chla molecules in purified CP43 and CP47 was calculated by comparing absorption and fluorescence excitation after normalization at 550 nm, CP43 had an energy transfer efficiency of 29.1% while the CP47 had an energy transfer efficiency of 62.8%, proving that excitation energy was transferred between p-Car and Chla molecules in CP43 and CP47 at normal conditions. The excitation energy transfer between p-Car and Chla molecules in CP43 and CP47 may occur through the "Dexter" mechanism and the distance between these two kinds of pigments should be less than 1 nm. In addition, the results were also used to discuss the conformational relationship between p-Car and Chla molecules in CP43 and CP47.
基金the National Natural Science Foundation of China !(No .39890 390 )
文摘Light and heat induced denaturation of CP47, the core antenna complex of photosystem Ⅱ purified from spinach, were investigated using absorption and circular dichroism spectra. Light caused the destruction of chlorophyll a and excitonic interaction of chlorophyll a in CP47, while the protein secondary structure was not apparently changed. Heat induced the destruction of protein secondary structure and excitonic interaction of chlorophyll a, but the chlorophyll a molecule was not damaged. The results suggest that both the chlorophyll a molecular structure and the protein native conformation are necessary for excitonic interaction of chlorophyll a and the energy transfer function of the chlorophyll a binding protein.
