施一公新实验室首篇Science

　　

生物通报道，继施一公教授Cell子刊的文章发表后，施一公教授又在Science上发表结构生物学研究成果，Structure and Mechanism of an Amino Acid Antiporter，这篇文章与两篇Cell子刊文章同天（5月28）上发布。

 

同期的Cell子刊文章：施一公2佳作齐登同期《细胞》子刊

 http://www.ebiotrade.com/newsf/2009-6/200964171124548.htm

 

文章的通讯作者是施一公教授，其他参与者工作单位都是清华大学。这是一篇施一公在中国的实验室发表的首篇Science文章。

 

这篇文章主要研究大肠杆菌的肠道毒性，大肠杆菌O157的肠道致病性主要依赖于细菌内的耐酸性系统，依靠这一系统，大肠杆菌能在PH偏酸的胃中生存。在耐酸系统中，主要依靠一种精氨酸依赖性的反向转运体（antiporter）。

 

施一公清华实验室主要研究大肠杆菌O157:H7的反向转运体AdiC的晶体结构。对AdiC的结构分析表明，AdiC结构保守，还获得了AdiC的配体结合残基结构。对分析耐酸系统中的反向转运体的功能机制具有重要的意义。

（生物通 小茜）

 

生物通推荐原文检索：

Structure and Mechanism of an Amino Acid Antiporter

Xiang Gao 1, Feiran Lu 1, Lijun Zhou 1, Shangyu Dang 1, Linfeng Sun 1, Xiaochun Li 1, Jiawei Wang 1, Yigong Shi 2*

1 State Key Laboratory of Bio-membrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China.; Center for Structural Biology, Department of Biological Sciences & Biotechnology, Tsinghua University, Beijing 100084, China.

2 Center for Structural Biology, Department of Biological Sciences & Biotechnology, Tsinghua University, Beijing 100084, China.; School of Medicine, Tsinghua University, Beijing 100084, China.

These author contributed equally to this work.

【Abstract】

Virulent enteric pathogens such as Escherichia coli strain O157:H7 rely on acid resistance (AR) systems to survive acidic environment in the stomach. A major component of AR is an arginine-dependent arginine:agmatine antiporter that expels intracellular protons. Here, we report the crystal structure of AdiC, the arginine:agmatine antiporter from E. coli O157:H7 and a member of the amino acid/polyamine/organocation (APC) superfamily of transporters at 3.6 Å resolution. The overall fold is similar to that of several Na+-coupled symporters. AdiC contains 12 transmembrane segments, forms a homodimer, and exists in an outward-facing, open conformation in the crystals. A conserved, acidic pocket opens to the periplasm. Structural and biochemical analysis reveals the essential ligand-binding residues, defines the transport route, and suggests a conserved mechanism for the antiporter activity.