Conformations of organic compounds in solution relate to their physical and chemical properties and biological activities. Two calix arene porphyrin derivatives were synthesized as models of cytochrome p 450 mono...Conformations of organic compounds in solution relate to their physical and chemical properties and biological activities. Two calix arene porphyrin derivatives were synthesized as models of cytochrome p 450 monooxygenase. The conformations of the models were determined using DQFCOSY (double quantum filter correlation spectroscopy), NOESY (nuclear overhauser effect spectroscopy), etc. The calix arene part showed cone conformation in the compound 1 and showed mainly partial cone conformation in the compound 2. The calix arene and the porphyrin were situated side by side in the compound 1, and above and below each other in the compound 2.展开更多
Calmodulin (CaM) is a multifunctional Ca 2+ binding regulatory protein with very important physiological functions. The properties of lanthanides (La 3+ ) are very similar to Ca 2+ .Their activity in livi...Calmodulin (CaM) is a multifunctional Ca 2+ binding regulatory protein with very important physiological functions. The properties of lanthanides (La 3+ ) are very similar to Ca 2+ .Their activity in living systems is usually related to competition with Ca 2+ . Therefore, the study of the interaction between lanthanides and CaM provides evidence for uncovering the functional mechanism of La 3+ in the Ca 2+ CaM enzyme system.In this report the coordination numbers and the binding sites of La 3+ on CaM were studied by using ion titration with one and two dimensional NMR. Their interactional mechanism was also discussed. After considering the effects of La 3+ on the chemical shift and on the intensity of the resonance peaks of Tyr 99, His 107 and Phe residues in 1H NMR , and after considering the effects on the correlation peaks in the 2D COSY NMR, it was concluded that the first La 3+ was bound near Tyr 99 and His 107 residues,i.e., near binding site III of Ca 2+ on CaM. This means the first La 3+ was bound the C terminal of CaM.The second and third La 3+ might have been bound on the CaM N terminal.展开更多
文摘Conformations of organic compounds in solution relate to their physical and chemical properties and biological activities. Two calix arene porphyrin derivatives were synthesized as models of cytochrome p 450 monooxygenase. The conformations of the models were determined using DQFCOSY (double quantum filter correlation spectroscopy), NOESY (nuclear overhauser effect spectroscopy), etc. The calix arene part showed cone conformation in the compound 1 and showed mainly partial cone conformation in the compound 2. The calix arene and the porphyrin were situated side by side in the compound 1, and above and below each other in the compound 2.
文摘Calmodulin (CaM) is a multifunctional Ca 2+ binding regulatory protein with very important physiological functions. The properties of lanthanides (La 3+ ) are very similar to Ca 2+ .Their activity in living systems is usually related to competition with Ca 2+ . Therefore, the study of the interaction between lanthanides and CaM provides evidence for uncovering the functional mechanism of La 3+ in the Ca 2+ CaM enzyme system.In this report the coordination numbers and the binding sites of La 3+ on CaM were studied by using ion titration with one and two dimensional NMR. Their interactional mechanism was also discussed. After considering the effects of La 3+ on the chemical shift and on the intensity of the resonance peaks of Tyr 99, His 107 and Phe residues in 1H NMR , and after considering the effects on the correlation peaks in the 2D COSY NMR, it was concluded that the first La 3+ was bound near Tyr 99 and His 107 residues,i.e., near binding site III of Ca 2+ on CaM. This means the first La 3+ was bound the C terminal of CaM.The second and third La 3+ might have been bound on the CaM N terminal.
