1HK9

Sm-Like Proteins in Eubacteria: The Crystal Structure of the Hfq Protein from Escherichia Coli

(2003) Nucleic Acids Res 31: 4091

• PubMed: 12853626 Search on PubMedSearch on PubMed Central
• DOI: https://doi.org/10.1093/nar/gkg480
• Primary Citation of Related Structures:  
  1HK9


• PubMed Abstract: 
  

  The Hfq protein was discovered in Escherichia coli in the early seventies as a host factor for the Qbeta phage RNA replication. During the last decade, it was shown to be involved in many RNA processing events and remote sequence homology indicated a link to spliceosomal Sm proteins. We report the crystal structure of the E.coli Hfq protein showing that its monomer displays a characteristic Sm-fold and forms a homo-hexamer, in agreement with former biochemical data. Overall, the structure of the E.coli Hfq ring is similar to the one recently described for Staphylococcus aureus. This confirms that bacteria contain a hexameric Sm-like protein which is likely to be an ancient and less specialized form characterized by a relaxed RNA binding specificity. In addition, we identified an Hfq ortholog in the archaeon Methanococcus jannaschii which lacks a classical Sm/Lsm gene. Finally, a detailed structural comparison shows that the Sm-fold is remarkably well conserved in bacteria, Archaea and Eukarya, and represents a universal and modular building unit for oligomeric RNA binding proteins.

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Organizational Affiliation: 

European Molecular Biology Laboratory, Structural and Computational Biology Programme, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.