Mycobacterium tuberculosis Rv2179c protein establishes a new exoribonuclease family with broad phylogenetic distribution

• Published in: The Journal of biological chemistry Vol. 289; no. 4; pp. 2139 - 2147
• Main Authors: Abendroth, Jan, Ollodart, Anja, Andrews, Emma S V, Myler, Peter J, Staker, Bart L, Edwards, Thomas E, Arcus, Vickery L, Grundner, Christoph
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 24.01.2014
• Subjects: Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Crystallography, X-Ray; Exoribonucleases - chemistry; Exoribonucleases - genetics; Exoribonucleases - metabolism; Humans; Microbiology; Mycobacterium tuberculosis - enzymology; Mycobacterium tuberculosis - genetics; Phylogeny; Structural Homology, Protein; Virulence Factors - chemistry; Virulence Factors - genetics; Virulence Factors - metabolism; Crystal Structure; Ribonuclease; Microbiology; Mycobacterium tuberculosis; Pseudomonas; Annotation
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M113.525683

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.