title: Crystallographic study of a MATE transporter presents a difficult case in structure determination with low-resolution, anisotropic data and crystal twinning.
abstract: NorM from Neisseria gonorrhoeae (NorM-NG) belongs to the multidrug and toxic compound extrusion (MATE) family of membrane-transport proteins, which can extrude cytotoxic chemicals across cell membranes and confer multidrug resistance. Here, the structure determination of NorM-NG is described, which had been hampered by low resolution (∼ 4 Å), data anisotropy and pseudo-merohedral twinning. The crystal structure was solved using molecular replacement and was corroborated by conducting a difference Fourier analysis. The NorM-NG structure displays an extracellular-facing conformation, similar to that of NorM-NG bound to a crystallization chaperone. The approaches taken to determine the NorM-NG structure and the lessons learned from this study are discussed, which may be useful for analyzing X-ray diffraction data with similar shortcomings.
authors.affiliation: Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA.
authors.forename: Jindrich
authors.initials: J
authors.lastname: Symersky
authors.affiliation: Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.
authors.forename: Jimin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Lu
mesh_terms: D016880:Anisotropy; D017920:Antiporters / Q000737:chemistry* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D005583:Fourier Analysis; D008024:Ligands; D008958:Models, Molecular; D009344:Neisseria gonorrhoeae / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D017920:Antiporters; D001426:Bacterial Proteins; D008024:Ligands; C114619:NorM protein, bacteria
keywords: MATE transporter; data anisotropy; difference Fourier analysis; multidrug resistance; twinning