Assembly of a fragmented ribonucleotide reductase by protein interaction domains derived from a mobile genetic element.
2011 (English)In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 39, no 4, 1381-9 p.Article in journal (Refereed) Published
Ribonucleotide reductase (RNR) is a critical enzyme of nucleotide metabolism, synthesizing precursors for DNA replication and repair. In prokaryotic genomes, RNR genes are commonly targeted by mobile genetic elements, including free standing and intron-encoded homing endonucleases and inteins. Here, we describe a unique molecular solution to assemble a functional product from the RNR large subunit gene, nrdA that has been fragmented into two smaller genes by the insertion of mobE, a mobile endonuclease. We show that unique sequences that originated during the mobE insertion and that are present as C- and N-terminal tails on the split NrdA-a and NrdA-b polypeptides, are absolutely essential for enzymatic activity. Our data are consistent with the tails functioning as protein interaction domains to assemble the tetrameric (NrdA-a/NrdA-b)(2) large subunit necessary for a functional RNR holoenzyme. The tails represent a solution distinct from RNA and protein splicing or programmed DNA rearrangements to restore function from a fragmented coding region and may represent a general mechanism to neutralize fragmentation of essential genes by mobile genetic elements.
Place, publisher, year, edition, pages
Oxford Journals , 2011. Vol. 39, no 4, 1381-9 p.
IdentifiersURN: urn:nbn:se:umu:diva-41107DOI: 10.1093/nar/gkq924PubMedID: 20972217OAI: oai:DiVA.org:umu-41107DiVA: diva2:404691