It was found for the first time that gramicidin D (GD) molecules can be incorporated into the ODM monolayer which is self-assembled on the surface of the gold electrode and form monovalent cation channels.
Gramicidin A(gA)is a kind of antibiotic peptide produced by bacillus brevis and it can dimerize across lipid bilayers to form a monovalent cation channel.In this work,we investigate the impact of cholesterol in the li...Gramicidin A(gA)is a kind of antibiotic peptide produced by bacillus brevis and it can dimerize across lipid bilayers to form a monovalent cation channel.In this work,we investigate the impact of cholesterol in the lipid bilayer on the binding of potassium ions with the gA channel and the transport of the ions across the channel.The results indicate that cholesterol can significantly influence the conformational stability of the gA channel and cause the channel deformation which inhibits the potassium ion binding with the channel and transport across the channel.The work provides some molecular insights into understanding of influence of lipids on the activity of gA channel in both model membranes and plasma membranes of intact cells.展开更多
In studies of ion channel systems,due to the huge computational cost of polarizable force elds,classical force elds remain the most widely used for a long time.In this work,we used the AMOEBA polarizable atomic multip...In studies of ion channel systems,due to the huge computational cost of polarizable force elds,classical force elds remain the most widely used for a long time.In this work,we used the AMOEBA polarizable atomic multipole force eld in enhanced sampling simula-tions of single-channel gramicidin A(gA)and double-channel gA systems and investigated its reliability in characterizing ion-transport properties of the gA ion channel under dimer-ization.The inuence of gA dimerization on the permeation of potassium and sodium ions through the channel was described in terms of conductance,di usion coeffcient,and free energy pro le.Results from the polarizable force eld simulations show that the conductance of potassium and sodium ions passing through the single-and double-channel agrees well with experimental values.Further data analysis reveals that the molecular mechanism of protein dimerization a ects the ion-transport properties of gA channels,i.e.,protein dimer-ization accelerates the permeation of potassium and sodium ions passing through the double-channel by adjusting the environment around gA protein(the distribution of phospholipid head groups,ions outside the channel,and bulk water),rather than directly adjusting the conformation of gA protein.展开更多
A serological kit was prepared for the first time to detect bacteria that produce Gramicidin (S). Since, an immunocomplex of antibiotic Gramicidin (S) was prepared followed by immunonization of laboratory animales to ...A serological kit was prepared for the first time to detect bacteria that produce Gramicidin (S). Since, an immunocomplex of antibiotic Gramicidin (S) was prepared followed by immunonization of laboratory animales to obtain specific antibodies in their serum. Serial dilutions of the prepared antibodies were tested directly against samples of bacteria and compared with control samples, which include bacteria that produce Gramicidin (S) (as a positive control) and the bacteria that does not produce Gramicidin (S) (as a negative control) depending slide method after the incubation of bacteria in a suitable media for 3 - 4 hours at 37°C. The prepared kites were evaluated in reference Laboratories and they proved to be highly sensitive (100%), specific (100%), more economic and reliable procedure, in addition to its stability for more than one year. It was the first time to prepare a kit for detection of bacteria which produce Gramicidin (S) directly within few minutes.展开更多
Changes of the behavior of the thermotropic phase transitions of the phospholipid DHPC by the action of miniprotein gramicidin D (G.D) have been studied by differential scanning calorimetry. The experimental results d...Changes of the behavior of the thermotropic phase transitions of the phospholipid DHPC by the action of miniprotein gramicidin D (G.D) have been studied by differential scanning calorimetry. The experimental results demonstrated that G.D could not remove the pretransition of DHPC, but the pretransition peak and the main transition peak of DHPC were incorporated into a broad peak. The pretransition temperature and the main transition temperature of DHPC decreased to different ex-tent. The sums of the pretransition and main transition enthalpies of DHPC showed a lineally decreasing relationship with increasing the mole fraction x_g of gramicidin D.展开更多
文摘It was found for the first time that gramicidin D (GD) molecules can be incorporated into the ODM monolayer which is self-assembled on the surface of the gold electrode and form monovalent cation channels.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674287)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY19A040009)。
文摘Gramicidin A(gA)is a kind of antibiotic peptide produced by bacillus brevis and it can dimerize across lipid bilayers to form a monovalent cation channel.In this work,we investigate the impact of cholesterol in the lipid bilayer on the binding of potassium ions with the gA channel and the transport of the ions across the channel.The results indicate that cholesterol can significantly influence the conformational stability of the gA channel and cause the channel deformation which inhibits the potassium ion binding with the channel and transport across the channel.The work provides some molecular insights into understanding of influence of lipids on the activity of gA channel in both model membranes and plasma membranes of intact cells.
基金This work is supported by the National Natural Sci-ence Foundation of China(No.21933010).
文摘In studies of ion channel systems,due to the huge computational cost of polarizable force elds,classical force elds remain the most widely used for a long time.In this work,we used the AMOEBA polarizable atomic multipole force eld in enhanced sampling simula-tions of single-channel gramicidin A(gA)and double-channel gA systems and investigated its reliability in characterizing ion-transport properties of the gA ion channel under dimer-ization.The inuence of gA dimerization on the permeation of potassium and sodium ions through the channel was described in terms of conductance,di usion coeffcient,and free energy pro le.Results from the polarizable force eld simulations show that the conductance of potassium and sodium ions passing through the single-and double-channel agrees well with experimental values.Further data analysis reveals that the molecular mechanism of protein dimerization a ects the ion-transport properties of gA channels,i.e.,protein dimer-ization accelerates the permeation of potassium and sodium ions passing through the double-channel by adjusting the environment around gA protein(the distribution of phospholipid head groups,ions outside the channel,and bulk water),rather than directly adjusting the conformation of gA protein.
文摘A serological kit was prepared for the first time to detect bacteria that produce Gramicidin (S). Since, an immunocomplex of antibiotic Gramicidin (S) was prepared followed by immunonization of laboratory animales to obtain specific antibodies in their serum. Serial dilutions of the prepared antibodies were tested directly against samples of bacteria and compared with control samples, which include bacteria that produce Gramicidin (S) (as a positive control) and the bacteria that does not produce Gramicidin (S) (as a negative control) depending slide method after the incubation of bacteria in a suitable media for 3 - 4 hours at 37°C. The prepared kites were evaluated in reference Laboratories and they proved to be highly sensitive (100%), specific (100%), more economic and reliable procedure, in addition to its stability for more than one year. It was the first time to prepare a kit for detection of bacteria which produce Gramicidin (S) directly within few minutes.
文摘Changes of the behavior of the thermotropic phase transitions of the phospholipid DHPC by the action of miniprotein gramicidin D (G.D) have been studied by differential scanning calorimetry. The experimental results demonstrated that G.D could not remove the pretransition of DHPC, but the pretransition peak and the main transition peak of DHPC were incorporated into a broad peak. The pretransition temperature and the main transition temperature of DHPC decreased to different ex-tent. The sums of the pretransition and main transition enthalpies of DHPC showed a lineally decreasing relationship with increasing the mole fraction x_g of gramicidin D.
