%0 
%0 Journal Article
%A Wagner, Steffen & Klug, Gabriele
%D 2007
%T An archaeal protein with homology to the eukaryotic translation initiation factor 5A shows ribonucleolytic activity
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%B The Journal of biological chemistry
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%I 
%V 282
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%N 
%P 13966-76
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%S 
%7
%8 May
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%Z 
%@ 00219258
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%3 article
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%F wagner_archaeal_2007
%K Amino_Acid_Sequence Archaeal Archaeal_Proteins Base_Sequence Cells Cultured Eukaryotic_Cells Genetic_Vectors Halobacterium IFZ Ligands Lysine Messenger Molecular_Sequence_Data Nucleic_Acid Nucleic_Acid_Conformation Peptide_Initiation_Factors Post-Translational Protein_Processing RNA RNA-Binding_Proteins Ribonucleases Sequence_Homology 
%X To identify proteins that are involved in RNA degradation and processing in Halobacterium sp. NRC-1, we purified proteins with RNA-degrading activity by classical biochemical techniques. One of these proteins showed strong homology to the eukaryotic initiation factor 5A (eIF-5A) and was accordingly named archaeal initiation factor 5A (aIF-5A). Eukaryotic IF-5A is known to be involved in mRNA turnover and to bind RNA. Hypusination of eIF-5A is required for sequence-specific binding of RNA. This unique post-translational modification is restricted to Eukarya and Archaea. The exact function of eIF-5A in RNA turnover remained obscure. Here we show for the first time that aIF-5A from Halobacterium sp. NRC-1 exhibits RNA cleavage activity, preferentially cleaving adjacent to A nucleotides. Detectable RNA binding could be shown for aIF-5A purified from Halobacterium sp. NRC-1 but not from Escherichia coli, while both proteins possess RNA cleavage activity, indicating that hypusination of aIF-5A is required for RNA binding but not for its RNA cleavage activity. Furthermore, we show that the hypusinated form of eIF-5A also shows RNase activity while the unmodified protein does not. Charged amino acids in the N-terminal domain of aIF-5A as well as in the C-terminal domain, which is highly similar to the cold shock protein A (CspA), an RNA chaperone of E. coli, are important for RNA cleavage activity. Moreover our results reveal that activity of aIF-5A depends on its oligomeric state.
%Z PMID: 17369252
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