title: Atomic resolution structure of the E. coli YajR transporter YAM domain.
abstract: YajR is an Escherichia coli transporter that belongs to the major facilitator superfamily. Unlike most MFS transporters, YajR contains a carboxyl terminal, cytosolic domain of 67 amino acid residues termed YAM domain. Although it is speculated that the function of this small soluble domain is to regulate the conformational change of the 12-helix transmembrane domain, its precise regulatory role remains unclear. Here, we report the crystal structure of the YAM domain at 1.07-Å resolution, along with its structure determined using nuclear magnetic resonance. Detailed analysis of the high resolution structure revealed a symmetrical dimer in which a belt of well-ordered poly-pentagonal water molecules is embedded. A mutagenesis experiment and a thermal stability assay were used to analyze the putative role of this dimerization in response to changes in halogen concentration.
authors: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
authors: Daohua
authors: D
authors: Jiang
authors: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China.
authors: Yan
authors: Y
authors: Zhao
authors: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
authors: Junping
authors: J
authors: Fan
authors: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
authors: Xuehui
authors: X
authors: Liu
authors: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
authors: Yan
authors: Y
authors: Wu
authors: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
authors: Wei
authors: W
authors: Feng
authors: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China. Electronic address: zhangc@ibp.ac.cn.
authors: Xuejun C
authors: XC
authors: Zhang
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D055503:Protein Multimerization; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D012965:Sodium Chloride / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C584948:YajR protein, E coli; D014867:Water; D012965:Sodium Chloride
keywords: Ferredoxin fold; MFS; Poly-pentagonal water network; YajR