title: Refolding, crystallization and preliminary X-ray crystallographic studies of the β-barrel domain of BamA, a membrane protein essential for outer membrane protein biogenesis.
abstract: In Gram-negative bacteria, the assembly of outer membrane proteins (OMPs) requires a five-protein β-barrel assembly machinery (BAM) complex, of which BamA is an essential and evolutionarily conserved integral outer membrane protein. Here, the refolding, crystallization and preliminary X-ray crystallographic characterization of the β-barrel domain of BamA from Escherichia coli (EcBamA) are reported. Native and selenomethionine-substituted EcBamA proteins were crystallized at 16°C and X-ray diffraction data were collected to 2.6 and 3.7 Å resolution, respectively. The native crystals belonged to space group P21212, with unit-cell parameters a = 118.492, b = 159.883, c = 56.000 Å and two molecules in one asymmetric unit; selenomethionine-substituted protein crystals belonged to space group P4322, with unit-cell parameters a = b = 163.162, c = 46.388 Å and one molecule in one asymmetric unit. Initial phases for EcBamA β-barrel domain were obtained from a SeMet SAD data set. These preliminary X-ray crystallographic studies paved the way for further structural determination of the β-barrel domain of EcBamA.
authors.affiliation: School of Public Health, Tianjin Medical University, Tianjin 300070, People's Republic of China.
authors.forename: Dongchun
authors.initials: D
authors.lastname: Ni
authors.affiliation: School of Public Health, Tianjin Medical University, Tianjin 300070, People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Yang
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000302:isolation & purification; D002850:Chromatography, Gel; D017124:Conserved Sequence; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D058849:Protein Refolding; D017433:Protein Structure, Secondary
chemical_list: D001425:Bacterial Outer Membrane Proteins; C503914:BamA protein, E coli; D029968:Escherichia coli Proteins
keywords: BamA; outer membrane protein biogenesis; protein refolding; β-barrel outer membrane protein