Mycobacterium tuberculosis Rv2179c Protein Establishes a New Exoribonuclease Family with Broad Phylogenetic Distribution |
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| Authors: | Jan Abendroth Anja Ollodart Emma S V Andrews Peter J Myler Bart L Staker Thomas E Edwards Vickery L Arcus Christoph Grundner |
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| Institution: | From ‡Emerald Bio, Bainbridge Island, Washington 98110.;the §Seattle Biomedical Research Institute, Seattle, Washington 98109.;the ¶Department of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand, and ;the **Department of Global Health, University of Washington, Seattle, Washington 98195 |
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| Abstract: | Ribonucleases (RNases) maintain the cellular RNA pool by RNA processing and degradation. In many bacteria, including the human pathogen Mycobacterium tuberculosis (Mtb), the enzymes mediating several central RNA processing functions are still unknown. Here, we identify the hypothetical Mtb protein Rv2179c as a highly divergent exoribonuclease. Although the primary sequence of Rv2179c has no detectable similarity to any known RNase, the Rv2179c crystal structure reveals an RNase fold. Active site residues are equivalent to those in the DEDD family of RNases, and Rv2179c has close structural homology to Escherichia coli RNase T. Consistent with the DEDD fold, Rv2179c has exoribonuclease activity, cleaving the 3′ single-strand overhangs of duplex RNA. Functional orthologs of Rv2179c are prevalent in actinobacteria and found in bacteria as phylogenetically distant as proteobacteria. Thus, Rv2179c is the founding member of a new, large RNase family with hundreds of members across the bacterial kingdom. |
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| Keywords: | Crystal Structure Microbiology Mycobacterium tuberculosis Pseudomonas Ribonuclease Annotation |
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