title: Structure determination of archaea-specific ribosomal protein L46a reveals a novel protein fold.
abstract: Three archaea-specific ribosomal proteins recently identified show no sequence homology with other known proteins. Here we determined the structure of L46a, the most conserved one among the three proteins, from Sulfolobus solfataricus P2 using NMR spectroscopy. The structure presents a twisted β-sheet formed by the N-terminal part and two helices at the C-terminus. The L46a structure has a positively charged surface which is conserved in the L46a protein family and is the potential rRNA-binding site. Searching homologous structures in Protein Data Bank revealed that the structure of L46a represents a novel protein fold. The backbone dynamics identified by NMR relaxation experiments reveal significant flexibility at the rRNA binding surface. The potential position of L46a on the ribosome was proposed by fitting the structure into a previous electron microscopy map of the ribosomal 50S subunit, which indicated that L46a contacts to domain I of 23S rRNA near a multifunctional ribosomal protein L7ae.
authors.affiliation: Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China. Electronic address: fengyg@qibebt.ac.cn.
authors.forename: Yingang
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Biological Science and Engineering, School of Chemical and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Xiaxia
authors.initials: X
authors.lastname: Song
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Jinzhong
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Biological Science and Engineering, School of Chemical and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Xuan
authors.affiliation: Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Cui
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D001665:Binding Sites; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D017386:Sequence Homology, Amino Acid
chemical_list: D019843:Archaeal Proteins; D012269:Ribosomal Proteins
keywords: Archaea; NMR; Protein fold; Protein structure; Ribosomal protein