title: Crystal structure of a conserved hypothetical protein MJ0927 from Methanocaldococcus jannaschii reveals a novel quaternary assembly in the Nif3 family.
abstract: A Nif3 family protein of Methanocaldococcus jannaschii, MJ0927, is highly conserved from bacteria to humans. Although several structures of bacterial Nif3 proteins are known, no structure representing archaeal Nif3 has yet been reported. The crystal structure of Methanocaldococcus jannaschii MJ0927 was determined at 2.47 Å resolution to understand the structural differences between the bacterial and archaeal Nif3 proteins. Intriguingly, MJ0927 is found to adopt an unusual assembly comprising a trimer of dimers that forms a cage-like architecture. Electrophoretic mobility-shift assays indicate that MJ0927 binds to both single-stranded and double-stranded DNA. Structural analysis of MJ0927 reveals a positively charged region that can potentially explain its DNA-binding capability. Taken together, these data suggest that MJ0927 adopts a novel quartenary architecture that could play various DNA-binding roles in Methanocaldococcus jannaschii.
authors.affiliation: Department of Biotechnology, Hungkuang University, Taichung 433, Taiwan ; Taiwan Advance Biopharm (TABP), Inc., Xizhi City, New Taipei City 221, Taiwan.
authors.forename: Sheng-Chia
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Department of Biotechnology, Hungkuang University, Taichung 433, Taiwan ; Taiwan Advance Biopharm (TABP), Inc., Xizhi City, New Taipei City 221, Taiwan.
authors.forename: Chi-Hung
authors.identifier: 0000-0002-8887-4962
authors.initials: CH
authors.lastname: Huang
authors.affiliation: Department of Biotechnology, Hungkuang University, Taichung 433, Taiwan ; Taiwan Advance Biopharm (TABP), Inc., Xizhi City, New Taipei City 221, Taiwan.
authors.forename: Chia Shin
authors.initials: CS
authors.lastname: Yang
authors.affiliation: Department of Biotechnology, Hungkuang University, Taichung 433, Taiwan.
authors.forename: Shu-Min
authors.initials: SM
authors.lastname: Kuan
authors.affiliation: School of Chinese Medicine, China Medical University, Taichung 40402, Taiwan.
authors.forename: Ching-Ting
authors.initials: CT
authors.lastname: Lin
authors.affiliation: Institute of Biochemistry and Agricultural Biotechnology Center, National Chung Hsing University, Taichung 40227, Taiwan.
authors.forename: Shan-Ho
authors.initials: SH
authors.lastname: Chou
authors.affiliation: Department of Biotechnology, Hungkuang University, Taichung 433, Taiwan.
authors.forename: Yeh
authors.identifier: 0000-0002-7740-0446
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D024202:Electrophoretic Mobility Shift Assay; D063747:Methanocaldococcus / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins