ATP-binding cassette (ABC) transporters use the energy of ATP hydrolysis to transport a large diversity of molecules actively across biological membranes. A combination of biochemical, biophysical, and structural studies has established the maltose transporter MalFGK2 as one of the best characterized proteins of the ABC family. MalF and MalG are the transmembrane domains, and two MalKs form a homodimer of nucleotide-binding domains. A periplasmic maltose-binding protein (MalE) delivers maltose and other maltodextrins to the transporter, and triggers its ATPase activity. Substrate import occurs in a unidirectional manner by ATP-driven conformational changes in MalK2 that allow alternating access of the substrate-binding site in MalF to each side of the membrane. In this review, we present an integrated molecular mechanism of the transport process considering all currently available information. Furthermore, we summarize remaining inconsistencies and outline possible future routes to decipher the full mechanistic details of transport by MalEFGK2 complex and that of related importer systems.

中文翻译：

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麦芽糖ABC进口商的综合运输机制。

ATP结合盒（ABC）转运蛋白利用ATP水解的能量来主动跨生物膜转运大量分子。生物化学，生物物理和结构研究相结合，建立了麦芽糖转运蛋白MalFGK2作为ABC家族中最有特色的蛋白质之一。MalF和MalG是跨膜结构域，两个MalKs形成核苷酸结合结构域的同型二聚体。周质麦芽糖结合蛋白（MalE）将麦芽糖和其他麦芽糖糊精递送至转运蛋白，并触发其ATPase活性。底物的导入通过ATP驱动的MalK2构象变化以单向方式发生，从而允许MalF中的底物结合位点交替进入膜的每一侧。在这篇评论中 我们考虑到所有当前可用的信息，提出了运输过程的综合分子机制。此外，我们总结了仍然存在的矛盾之处，并概述了可能的未来路线，以破译MalEFGK2复合体和相关进口商系统的完整运输机械细节。