ABC transporters form the largest of all transporter families, and their structural study has made tremen- dous progress over recent years. However, despite such advances, the precise mechanisms that determine the ene...ABC transporters form the largest of all transporter families, and their structural study has made tremen- dous progress over recent years. However, despite such advances, the precise mechanisms that determine the energy-coupling between ATP hydrolysis and the con- formational changes following substrate binding remain to be elucidated. Here, we present our thermodynamic analysis for both ABC importers and exporters, and introduce the two new concepts of differential-binding energy and elastic conformational energy into the dis- cussion. We hope that the structural analysis of ABC transporters will henceforth take thermodynamic aspects of transport mechanisms into account as well.展开更多
G-protein coupled receptors （GPCRs） play an essential role in eukaryotic cells signaling. According to phylogenetic analysis, most GPCRs belong to one of four classes, i.e. A, B, C, and Frizzled （Lagerstrom and Sch...G-protein coupled receptors （GPCRs） play an essential role in eukaryotic cells signaling. According to phylogenetic analysis, most GPCRs belong to one of four classes, i.e. A, B, C, and Frizzled （Lagerstrom and Schioth, 2008）. The class-C GPCR family contains metabotropic glutamate receptors （mGluR）, y-aminobutyric acid B receptors （GABAB receptor or GBR）, several taste-sensing receptors （e.g.展开更多
Integral membrane proteins （MPs） are categorized into two major groups： transmembrane （TM） α-helical bundles and β-barrels （Cymer et al., 2014）. Both types of structures permit the backbones of their peptides...Integral membrane proteins （MPs） are categorized into two major groups： transmembrane （TM） α-helical bundles and β-barrels （Cymer et al., 2014）. Both types of structures permit the backbones of their peptides to fulfill their hydro- gen-bonding potential in a lipid-bilayer environment. The thermal stability of a typical β-barrel MP is usually much higher than that of a helical MP. Thus, β-barrel MPs are able to withstand near boiling-temperatures during purification （Han et al., 2016）, compared with the typical melting tem- peratures of 50℃ or lower for a-helical TM proteins. In fact, unfolding a β-barrel MP in a single-molecule assay typically requires multiple steps, each of which requires a force of 100-300 pN （Thoma et al., 2015）. Considering the thickness of the membrane as well as the multiple steps, unfolding one mole of β-barrel MP molecules would require -103 kJ of energy （equivalent to 400 RT or energy from hydrolyzing 20-30 moles of ATP）. Such high thermal stability is consid- ered to be the sole source of the energy that drives the folding of β-barrel MPs （Fleming, 2015）.China展开更多
文摘ABC transporters form the largest of all transporter families, and their structural study has made tremen- dous progress over recent years. However, despite such advances, the precise mechanisms that determine the energy-coupling between ATP hydrolysis and the con- formational changes following substrate binding remain to be elucidated. Here, we present our thermodynamic analysis for both ABC importers and exporters, and introduce the two new concepts of differential-binding energy and elastic conformational energy into the dis- cussion. We hope that the structural analysis of ABC transporters will henceforth take thermodynamic aspects of transport mechanisms into account as well.
文摘G-protein coupled receptors （GPCRs） play an essential role in eukaryotic cells signaling. According to phylogenetic analysis, most GPCRs belong to one of four classes, i.e. A, B, C, and Frizzled （Lagerstrom and Schioth, 2008）. The class-C GPCR family contains metabotropic glutamate receptors （mGluR）, y-aminobutyric acid B receptors （GABAB receptor or GBR）, several taste-sensing receptors （e.g.
基金the National Basic Research Program （973 Program） （No. 2014CB910104）, the Chinese Acad- emy of Sciences （No. XDB08020301）, and the National Natural Science Foundation of China （Grant No. 31470745）.
文摘Integral membrane proteins （MPs） are categorized into two major groups： transmembrane （TM） α-helical bundles and β-barrels （Cymer et al., 2014）. Both types of structures permit the backbones of their peptides to fulfill their hydro- gen-bonding potential in a lipid-bilayer environment. The thermal stability of a typical β-barrel MP is usually much higher than that of a helical MP. Thus, β-barrel MPs are able to withstand near boiling-temperatures during purification （Han et al., 2016）, compared with the typical melting tem- peratures of 50℃ or lower for a-helical TM proteins. In fact, unfolding a β-barrel MP in a single-molecule assay typically requires multiple steps, each of which requires a force of 100-300 pN （Thoma et al., 2015）. Considering the thickness of the membrane as well as the multiple steps, unfolding one mole of β-barrel MP molecules would require -103 kJ of energy （equivalent to 400 RT or energy from hydrolyzing 20-30 moles of ATP）. Such high thermal stability is consid- ered to be the sole source of the energy that drives the folding of β-barrel MPs （Fleming, 2015）.China
