Hydrolysis reaction of L-a-dipalmitoylphosphatidylcholine (L-DPPC) monolayer with phospholipase D (PLD) has been investigated by Brewster angle microscopy (BAM) combined with the film balance. It has been found that ...Hydrolysis reaction of L-a-dipalmitoylphosphatidylcholine (L-DPPC) monolayer with phospholipase D (PLD) has been investigated by Brewster angle microscopy (BAM) combined with the film balance. It has been found that the L-DPPC domains were changed into the 搇otus?structure by PLD. It suggests that the hydrolysis reaction is incomplete and the products together with the nonreacted materials undergo a molecular rearrangement at the interface.展开更多
On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine （DPPC） and dipalmitoylphosphatidylglycerol （DPPG） in pure phospholipid rnono...On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine （DPPC） and dipalmitoylphosphatidylglycerol （DPPG） in pure phospholipid rnonolayer at the air/water interface during compression are derived. The optimized conformations of phospholipids at absolute freedom state are simulated by Gaussian 98 software. Based on following assumptions： （1） the conformation energy change is mainly caused by the rotation of one special bond; （2） the atoms of glycerol near the water surface are active; （3） the rotation is motivated by hydrogen-bond action; （4） the rotation of bond is inertial, one simplified track of conformational change is suggested and the conformations of DPPC and DPPG at different states are determined by the plots of conformation energy change vs. dihedral angle. The thickness of the simulated phospholipid monolayer is consistent with published experimental result. According to molecular areas at different states, the molecular orientations in the compressing process are also developed.展开更多
C reactive protein (CRP) is a major acute phase reactant in most mammalian species. The recognition and the binding principles of CRP to its substrates are not well known. In this paper the interaction of rabbit ...C reactive protein (CRP) is a major acute phase reactant in most mammalian species. The recognition and the binding principles of CRP to its substrates are not well known. In this paper the interaction of rabbit CRP (rCRP) with lipid monolayers at the air/water interface was studied. From the experiments it was concluded that rCRP molecules were amphipathic, and rCRP molecules might interact with phospholipid monolayers by hydrophobic force. The critical surface pressure of rCRP interacting with phospholipid monolayers is about 34 5 mN/m.展开更多
Synaptotagmin Ⅰ(sytⅠ) is an abundant integral membrane protein of the synaptic vesicle and the C2A domain is an important functional domain in the cytoplasmic part of sytⅠ. C2A prefers to interact with plasmic me...Synaptotagmin Ⅰ(sytⅠ) is an abundant integral membrane protein of the synaptic vesicle and the C2A domain is an important functional domain in the cytoplasmic part of sytⅠ. C2A prefers to interact with plasmic membranes of neuron cells in vivo and such interaction is closely related to the sytⅠ physiological function as a Ca 2+ sensor in the Ca 2+ regulated neurotransmitter release. However, the interaction nature between C2A and phospholipids is not well understood. Monolayers at an air/water interface were used to study the interaction between C2A and a phospholipid membrane. The results show that C2A preferentially inserts into the negatively charged phosphatidylserine monolayer and Ca 2+ ions are required for the interaction. Electrostatic force is mostly responsible for the insertion of C2A into dipalmitoyl phosphatidylserine monolayers.展开更多
基金supported by NNSFC(NO.29925307)as well as the research contract between the German Max-Planck-Society and the Chinese Academy of Sciences.
文摘Hydrolysis reaction of L-a-dipalmitoylphosphatidylcholine (L-DPPC) monolayer with phospholipase D (PLD) has been investigated by Brewster angle microscopy (BAM) combined with the film balance. It has been found that the L-DPPC domains were changed into the 搇otus?structure by PLD. It suggests that the hydrolysis reaction is incomplete and the products together with the nonreacted materials undergo a molecular rearrangement at the interface.
基金Supported by the National Natural Science Foundation of China （20876047）.
文摘On the basis of energy conservation law and surface pressure isotherm, the conformation energy changes of dipalmitoylphosphatidylcholine （DPPC） and dipalmitoylphosphatidylglycerol （DPPG） in pure phospholipid rnonolayer at the air/water interface during compression are derived. The optimized conformations of phospholipids at absolute freedom state are simulated by Gaussian 98 software. Based on following assumptions： （1） the conformation energy change is mainly caused by the rotation of one special bond; （2） the atoms of glycerol near the water surface are active; （3） the rotation is motivated by hydrogen-bond action; （4） the rotation of bond is inertial, one simplified track of conformational change is suggested and the conformations of DPPC and DPPG at different states are determined by the plots of conformation energy change vs. dihedral angle. The thickness of the simulated phospholipid monolayer is consistent with published experimental result. According to molecular areas at different states, the molecular orientations in the compressing process are also developed.
文摘C reactive protein (CRP) is a major acute phase reactant in most mammalian species. The recognition and the binding principles of CRP to its substrates are not well known. In this paper the interaction of rabbit CRP (rCRP) with lipid monolayers at the air/water interface was studied. From the experiments it was concluded that rCRP molecules were amphipathic, and rCRP molecules might interact with phospholipid monolayers by hydrophobic force. The critical surface pressure of rCRP interacting with phospholipid monolayers is about 34 5 mN/m.
文摘Synaptotagmin Ⅰ(sytⅠ) is an abundant integral membrane protein of the synaptic vesicle and the C2A domain is an important functional domain in the cytoplasmic part of sytⅠ. C2A prefers to interact with plasmic membranes of neuron cells in vivo and such interaction is closely related to the sytⅠ physiological function as a Ca 2+ sensor in the Ca 2+ regulated neurotransmitter release. However, the interaction nature between C2A and phospholipids is not well understood. Monolayers at an air/water interface were used to study the interaction between C2A and a phospholipid membrane. The results show that C2A preferentially inserts into the negatively charged phosphatidylserine monolayer and Ca 2+ ions are required for the interaction. Electrostatic force is mostly responsible for the insertion of C2A into dipalmitoyl phosphatidylserine monolayers.
