Structure and Mechanism of a Nitrate Transporter

被引：78

作者：

Yan, Hanchi ^{[1
,3
,4
]}

Huang, Weiyun ^{[1
,3
,4
]}

Yan, Chuangye ^{[1
,3
,4
]}

Gong, Xinqi ^{[1
,3
,4
]}

Jiang, Sirui ^{[1
,3
,4
]}

Zhao, Yu ^{[1
,3
,4
]}

Wang, Jiawei ^{[2
,3
,4
]}

Shi, Yigong ^{[1
,3
,4
]}

机构：

[1] Tsinghua Univ, Minist Educ, Key Lab Prot Sci, Beijing 100084, Peoples R China

[2] Tsinghua Univ, State Key Lab Biomembrane & Membrane Biotechnol, Beijing 100084, Peoples R China

[3] Tsinghua Univ, Tsinghua Peking Joint Ctr Life Sci, Struct Biol Ctr, Sch Life Sci, Beijing 100084, Peoples R China

[4] Tsinghua Univ, Sch Med, Beijing 100084, Peoples R China

来源：

CELL REPORTS | 2013年 / 3卷 / 03期

基金：

中国国家自然科学基金;

关键词：

NITRITE TRANSPORT; NARU; NIRC; ARABIDOPSIS; RESIDUES; CHANNEL; PROTEIN; SYSTEM; FAMILY; NRT2.1;

D O I：

10.1016/j.celrep.2013.03.007

中图分类号：

Q2 [细胞生物学];

学科分类号：

071009 ; 090102 ;

摘要：

The nitrate/nitrite transporters NarK and NarU play an important role in nitrogen homeostasis in bacteria and belong to the nitrate/nitrite porter family (NNP) of the major facilitator superfamily (MFS) fold. The structure and functional mechanism of NarK and NarU remain unknown. Here, we report the crystal structure of NarU at a resolution of 3.1A and systematic biochemical characterization. The two molecules of NarU in an asymmetric unit exhibit two distinct conformational states: occluded and partially inward-open. The substrate molecule nitrate appears to be coordinated by four highly conserved, charged, or polar amino acids. Structural and biochemical analyses allowed the identification of key amino acids that are involved in substrate gating and transport. The observed conformational differences of NarU, together with unique sequence features of the NNP family transporters, suggest a transport mechanism that might deviate from the canonical rocker-switch model.

引用

页码：716 / 723

页数：8

共 39 条

[1] Structure and mechanism of the lactose permease of Escherichia coli [J].