The history of antiparallel coiled coil dimer design is briefly reviewed and the main principles governing the successful designs are explained. They include analysis of the inter subunit electrostatic repulsion for ...The history of antiparallel coiled coil dimer design is briefly reviewed and the main principles governing the successful designs are explained. They include analysis of the inter subunit electrostatic repulsion for determining partners for dimerization and of the buried polar interaction for determining the relative orientation of the partners. A theory is proposed to explain the lack of antiparallel coiled coil homodimers in nature.展开更多
The stability of GCN4 leucine zipper and its four mutants in guanidine hydrochloride was detected to verify the contributions of different a position amino acid residues in polypeptide sequences to the forming and sta...The stability of GCN4 leucine zipper and its four mutants in guanidine hydrochloride was detected to verify the contributions of different a position amino acid residues in polypeptide sequences to the forming and stability of parallel coiled coils. The changes of the circular dichroism spectra show that the displace- ment of the a position polar asparagine and the increase of asparagine in the GCN4 leucine zipper can reduce the α-helix content of the coiled coil structure. The mutants are less stable than the natural peptide in guanidine hydrochloride. The results show that the interaction between the polar asparagine contributes to the conformational stability of the coiled coil. Both the conformation and the number of polar residues in the coiled coil also affect the α-helix content and its resistance to the denaturant. The conclusions provide evidence describing the folding process of proteins including coiled coils in vivo.展开更多
To understand the biocompatibility of alginate, the effect of alginate on a biomembrane was studied by using a liposome as a biomembrane model. Polarized fluorescence spectroscopy, differential scanning calorimetry (...To understand the biocompatibility of alginate, the effect of alginate on a biomembrane was studied by using a liposome as a biomembrane model. Polarized fluorescence spectroscopy, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and electron microscopy (EM) were used in this work. Fluorescent and DSC results have shown that alginate immobilization increased membrane fluidity and the T c of the membrane lipid. The FTIR results demonstrated that alginate entrapment induced no significant changes in membrane lipid chemical bonds.Freeze fracture analysis revealed lipids in the two dimensional monoclinic lattice state, P β′ , in the DPPC (dipalmitoyl phosphatidylcholine) liposome/sodium alginate mixture at room temperature, a much lower temperature than the pre transition temperature of the DPPC liposome .展开更多
基金the"973" Projectthe Natural ScienceFoundation of Guangdongthe Research Foundationfor Returned Overseas Scholars of the Ministry ofEducationthe State Key L ab of Biomembrane &Membrane Biotechnology
文摘The history of antiparallel coiled coil dimer design is briefly reviewed and the main principles governing the successful designs are explained. They include analysis of the inter subunit electrostatic repulsion for determining partners for dimerization and of the buried polar interaction for determining the relative orientation of the partners. A theory is proposed to explain the lack of antiparallel coiled coil homodimers in nature.
基金Supported by the National Natural Science Foundation of China (No. 30170199) and the Basic Research Foundation of Tsinghua University (No. JC2003050)
文摘The stability of GCN4 leucine zipper and its four mutants in guanidine hydrochloride was detected to verify the contributions of different a position amino acid residues in polypeptide sequences to the forming and stability of parallel coiled coils. The changes of the circular dichroism spectra show that the displace- ment of the a position polar asparagine and the increase of asparagine in the GCN4 leucine zipper can reduce the α-helix content of the coiled coil structure. The mutants are less stable than the natural peptide in guanidine hydrochloride. The results show that the interaction between the polar asparagine contributes to the conformational stability of the coiled coil. Both the conformation and the number of polar residues in the coiled coil also affect the α-helix content and its resistance to the denaturant. The conclusions provide evidence describing the folding process of proteins including coiled coils in vivo.
文摘To understand the biocompatibility of alginate, the effect of alginate on a biomembrane was studied by using a liposome as a biomembrane model. Polarized fluorescence spectroscopy, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and electron microscopy (EM) were used in this work. Fluorescent and DSC results have shown that alginate immobilization increased membrane fluidity and the T c of the membrane lipid. The FTIR results demonstrated that alginate entrapment induced no significant changes in membrane lipid chemical bonds.Freeze fracture analysis revealed lipids in the two dimensional monoclinic lattice state, P β′ , in the DPPC (dipalmitoyl phosphatidylcholine) liposome/sodium alginate mixture at room temperature, a much lower temperature than the pre transition temperature of the DPPC liposome .
