论文标题
能量运输及其在七型跨膜蛋白中的功能
Energy Transport and its Function in Heptahelical Transmembrane Proteins
论文作者
论文摘要
诸如细菌紫红素（BR）和视紫红质（Rho）等光蛋白需要有效散发光诱导的过量能量，以防止其损害。 B2肾上腺螺旋螺旋（TM）螺旋的另一个良好研究的G蛋白偶联受体（GPCR）是B2肾上腺素能受体（B2AR），为此，能量耗散路径与变构通信有关。为了研究这些GPCR的主动和非活性状态的振动能传输，一种主方程方法[J.化学物理。使用152，045103（2020）]，它使用缩放规则，允许仅根据蛋白质结构来计算能量传输速率。尽管具有结构性相似，但这三个GPCR揭示了重新分配多余能量的策略截然不同。虽然BR使用TM7螺旋作为“避雷针”迅速消除了能量，但Rho表现出相当差的能量耗散，最终可能需要在蛋白质和视网膜发色团之间水解Schiff碱基的水解以防止过热。加热B2AR的配体肾上腺素，发现蛋白质的能量传输网络在从活动状态转换为无活性状态后会发生显着变化。虽然能量流可以突出B2AR的跨层次耦合的各个方面，但似乎并不特别适合解释变构现象。
Photoproteins such as bacteriorhodopsin (bR) and rhodopsin (Rho) need to effectively dissipate photoinduced excess energy to prevent their damage. Another well-studied G protein-coupled receptor (GPCR) containing 7 transmembrane (TM) helices is the B2 adrenergic receptor (B2AR), for which energy dissipation paths have been linked with allosteric communication. To study the vibrational energy transport in the active and inactive states of these GPCRs, a master equation approach [J. Chem. Phys. 152, 045103 (2020)] is employed, which uses scaling rules that allow to calculate energy transport rates solely based on the protein structure. Despite their structural similarities, the three GPCRs reveal quite different strategies to redistribute excess energy. While bR quickly removes the energy using the TM7 helix as a "lightning rod", Rho exhibits a rather poor energy dissipation, which might eventually require the hydrolysis of the Schiff base between the protein and the retinal chromophore to prevent overheating. Heating the ligand adrenaline of B2AR, the resulting energy transport network of the protein is found to change significantly upon switching from the active to the inactive state. While the energy flow may highlight aspects of the interresidue couplings of B2AR, it seems not particularly suited to explain allosteric phenomena.
