克氏柠檬酸杆菌Sat_Ck的x-射线成像数据集

醋酸盐是代谢和细胞信号传导的重要代谢物。琥珀酸醋酸盐通透酶（SatP）超家族蛋白已知负责醋酸盐跨膜转运，但这种转运的性质尚不清楚。在这里我们表明，克氏柠檬酸杆菌的SatP同系物（SatP_Ck）是一种阴离子通道，可以以约107个离子/秒的速率单向转运醋酸盐。SatP_Ck与多个醋酸根在1.8Å的复合物的晶体结构表明，醋酸根通道由四个醋酸根结合位点组成，这些结合位点排列成一条线，并被三个疏水性收缩点打断。四个乙酸根结合位点方向各不相同。位于细胞质前庭的醋酸根处于部分脱水状态，而主孔体的醋酸根完全脱水。底物运输通道中的芳香残基可能通过阴离子-π相互作用协调乙酸根的易位。SatP_Ck揭示了一种新型的选择性阴离子通道，并为理解有机阴离子转运提供了结构和功能模板。

Acetate is a critical metabolite for both metabolism and cell signaling. Members of the succinate-acetate permease (SatP) superfamily are known to mediate transmembrane acetate transport, yet the underlying mechanism of this transport remains elusive. Here, we demonstrate that the SatP homologue from Citrobacter koseri (SatP_Ck) functions as an anion channel that unidirectionally transports acetate at a rate of approximately 10^7 ions per second. The crystal structure of the SatP_Ck complex with multiple acetate ions at 1.8 Å resolution reveals that the acetate channel is composed of four linearly arranged acetate-binding sites, which are interrupted by three hydrophobic constrictions. All four acetate-binding sites exhibit distinct orientations. Acetate ions located in the cytoplasmic vestibule are partially dehydrated, whereas those within the central pore are fully dehydrated. Aromatic residues in the substrate transport channel may facilitate acetate translocation via anion-π interactions. SatP_Ck uncovers a novel class of selective anion channels, and provides a structural and functional template for understanding organic anion transport.

搜集汇总

背景与挑战

背景概述

该数据集提供了克氏柠檬酸杆菌Sat_Ck的X射线成像数据，用于研究琥珀酸醋酸盐通透酶（SatP_Ck）作为阴离子通道的结构与功能。它揭示了醋酸根单向转运的机制和通道的晶体结构，为理解有机阴离子转运提供了重要的结构和功能模板。