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O-Carbamoyltransferase TobZ

  1. Stefan Görlich,
  2. Christoph Parthier,
  3. Uwe Fandrich,
  4. Milton T Stubbs

Published Online: 3 SEP 2013

DOI: 10.1002/9781119951438.eibc2175

Encyclopedia of Inorganic and Bioinorganic Chemistry

Encyclopedia of Inorganic and Bioinorganic Chemistry

How to Cite

Görlich, S., Parthier, C., Fandrich, U. and Stubbs, M. T. 2013. O-Carbamoyltransferase TobZ. Encyclopedia of Inorganic and Bioinorganic Chemistry. .

Author Information

  1. Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany

Publication History

  1. Published Online: 3 SEP 2013

Abstract

O-carbamoyltransferases, which modify a variety of natural products, exhibit an intriguing requirement for ATP. The structure of the 6″-O-carbamoyltransferase TobZ, responsible for biotransformation of the aminoglycoside antibiotic tobramycin to form nebramycin 5′, reveals two modular domains each harboring an active center within a common “reaction chamber”. The C-terminal YrdC-like domain harbors a carbamoylphosphate-binding site, occupation of which triggers Mg2+–ATP binding and the subsequent formation of carbamoyladenylate. The adenylated intermediate is channeled to an iron-mediated nucleotide-binding site within the N-terminal Kae1-like domain, where the carbamoyl moiety is transferred to the tobramycin acceptor hydroxyl group. Conservation of modules within the hydrogenase maturation factor HypF as well as components of the ubiquitous threonylcarbamoyladenosine-tRNA modification apparatus suggests analogous reaction sequences and points to an ancient origin of these proteins.

3D Structure

  • original image

    Schematic representation of TobZ from Streptoalloteichus tenebrarius (pdb code: 3VET).4 The N-terminal Kae1-like domain (brown, β-finger lilac) harbors the bound Fe-atom (orange sphere) and has a binding site for adenosine nucleotides (ADP, yellow) and the terminal acceptor tobramycin (cyan). The C-terminal YrdC-like domain (blue) receives the donor substrate carbamoyl phosphate (yellow) and binds adenosine nucleotides (in this case, the inhibitor ADP, green) in the presence of divalent cations (Mn2+, magenta). All structural figures were prepared using the program PyMOL (Schrödinger, LLC, http://www.schrodinger.com).

Keywords:

  • antibiotic biosynthesis;
  • aminoglycoside;
  • secondary metabolite;
  • substrate-assisted catalysis;
  • substrate channeling;
  • adenylation;
  • structural enzymology;
  • tRNA modification;
  • hydrogenase maturation;
  • enzyme evolution