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PLoS One. 2014 Jun 10;9(6):e98729. doi: 10.1371/journal.pone.0098729. eCollection 2014.

Protozoan ALKBH8 oxygenases display both DNA repair and tRNA modification activities.

Author information

1
Department of Biosciences, University of Oslo, Oslo, Norway; Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland.
2
Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
3
Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
4
Department of Biosciences, University of Oslo, Oslo, Norway.
5
Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland; Department of Neurophysiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
6
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
7
Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
8
Institute of Genetics and Biotechnology, University of Warsaw, Warsaw, Poland; Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.

Abstract

The ALKBH family of Fe(II) and 2-oxoglutarate dependent oxygenases comprises enzymes that display sequence homology to AlkB from E. coli, a DNA repair enzyme that uses an oxidative mechanism to dealkylate methyl and etheno adducts on the nucleobases. Humans have nine different ALKBH proteins, ALKBH1-8 and FTO. Mammalian and plant ALKBH8 are tRNA hydroxylases targeting 5-methoxycarbonylmethyl-modified uridine (mcm5U) at the wobble position of tRNAGly(UCC). In contrast, the genomes of some bacteria encode a protein with strong sequence homology to ALKBH8, and robust DNA repair activity was previously demonstrated for one such protein. To further explore this apparent functional duality of the ALKBH8 proteins, we have here enzymatically characterized a panel of such proteins, originating from bacteria, protozoa and mimivirus. All the enzymes showed DNA repair activity in vitro, but, interestingly, two protozoan ALKBH8s also catalyzed wobble uridine modification of tRNA, thus displaying a dual in vitro activity. Also, we found the modification status of tRNAGly(UCC) to be unaltered in an ALKBH8 deficient mutant of Agrobacterium tumefaciens, indicating that bacterial ALKBH8s have a function different from that of their eukaryotic counterparts. The present study provides new insights on the function and evolution of the ALKBH8 family of proteins.

PMID:
24914785
PMCID:
PMC4051686
DOI:
10.1371/journal.pone.0098729
[Indexed for MEDLINE]
Free PMC Article

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