5J4I

Crystal Structure of the L-arginine/agmatine antiporter from E. coli at 2.2 Angstroem resolution

5J4I の概要

• エントリーDOI: 10.2210/pdb5j4i/pdb
• 分子名称: Arginine/agmatine antiporter (2 entities in total)
• 機能のキーワード: adic, transporter, membrane protein, transport protein
• 由来する生物種: Escherichia coli O157:H7
• 細胞内の位置: Cell inner membrane ; Multi- pass membrane protein : P60063
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 95682.77

構造登録者

Jeckelmann, J.M.,Ilgue, H.,Fotiadis, D. (登録日: 2016-04-01, 公開日: 2016-08-31, 最終更新日: 2024-01-10)

主引用文献

Ilgu, H.,Jeckelmann, J.M.,Gapsys, V.,Ucurum, Z.,de Groot, B.L.,Fotiadis, D.
Insights into the molecular basis for substrate binding and specificity of the wild-type L-arginine/agmatine antiporter AdiC.
Proc.Natl.Acad.Sci.USA, 113:10358-10363, 2016

PubMed Abstract: Pathogenic enterobacteria need to survive the extreme acidity of the stomach to successfully colonize the human gut. Enteric bacteria circumvent the gastric acid barrier by activating extreme acid-resistance responses, such as the arginine-dependent acid resistance system. In this response, l-arginine is decarboxylated to agmatine, thereby consuming one proton from the cytoplasm. In Escherichia coli, the l-arginine/agmatine antiporter AdiC facilitates the export of agmatine in exchange of l-arginine, thus providing substrates for further removal of protons from the cytoplasm and balancing the intracellular pH. We have solved the crystal structures of wild-type AdiC in the presence and absence of the substrate agmatine at 2.6-Å and 2.2-Å resolution, respectively. The high-resolution structures made possible the identification of crucial water molecules in the substrate-binding sites, unveiling their functional roles for agmatine release and structure stabilization, which was further corroborated by molecular dynamics simulations. Structural analysis combined with site-directed mutagenesis and the scintillation proximity radioligand binding assay improved our understanding of substrate binding and specificity of the wild-type l-arginine/agmatine antiporter AdiC. Finally, we present a potential mechanism for conformational changes of the AdiC transport cycle involved in the release of agmatine into the periplasmic space of E. coli.

PubMed: 27582465
DOI: 10.1073/pnas.1605442113

実験手法

X-RAY DIFFRACTION (2.207 Å)