Replacement of the cobalt center of vitamin B12 by nickel: Nibalamin and nibyric acid prepared from metal-free B12 ligands hydrogenobalamin and hydrogenobyric acid

Christoph Kieninger, Klaus Wurst, Maren Podewitz, Maria Stanley, Evelyne Deery, Andrew D. Lawrence, Klaus R. Liedl, Martin J. Warren, Bernhard Kräutler

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The (formal) replacement of Co in cobalamin (Cbl) by NiII generates nibalamin (Nibl), a new transition-metal analogue of vitamin B12. Described here is Nibl, synthesized by incorporation of a NiII ion into the metal-free B12 ligand hydrogenobalamin (Hbl), itself prepared from hydrogenobyric acid (Hby). The related NiII corrin nibyric acid (Niby) was similarly synthesized from Hby, the metal-free cobyric acid ligand. The solution structures of Hbl, and Niby and Nibl, were characterized by spectroscopic studies. Hbl features two inner protons bound at N2 and N4 of the corrin ligand, as discovered in Hby. X-ray analysis of Niby shows the structural adaptation of the corrin ligand to NiII ions and the coordination behavior of NiII. The diamagnetic Niby and Nibl, and corresponding isoelectronic CoI corrins, were deduced to be isostructural. Nibl is a structural mimic of four-coordinate base-off Cbls, as verified by its ability to act as a strong inhibitor of bacterial adenosyltransferase.

Original languageEnglish
Pages (from-to)20129-20136
Number of pages8
JournalAngewandte Chemie - International Edition
Issue number45
Early online date20 Jul 2020
Publication statusPublished - 2 Nov 2020


  • cobalamins
  • crystal structures
  • porphyrinoids
  • transition metals
  • vitamins

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