The structure of a valinomycin–hexaaquamagnesium trifluoromethanesulfonate compound

Megumi Fujita, Amaan M. Kazerouni, John Bacsa
  • Acta Crystallographica Section C Structural Chemistry, July 2016, International Union of Crystallography
  • DOI: 10.1107/s2053229616010676

New metal ion binding mode of valinomycin, incorporating the whole hexaaqua complex

What is it about?

The antibiotic macrocycle valinomycin gulps up a large hexaaquamagnesium complex [Mg(H2O)6]2+. This reveals yet another cation-binding mode of valinomycin, which is known to selective K+ carrier. A beautiful three-fold crystal network, including the counter-ion trifluoromethanesulfonate, is exhibited in the crystal structure.

Why is it important?

This work reveals valinomycin's versatile ability to bind cations, including a fully hydrated cation through hydrogen-bonding, not by direct coordination, as showcased in this work. Valinomycin has been known since 1960's, and the most crystal structures were published in the 60's to 80's. Then the structural investigation seemed to have stopped for a while. This is our 3rd publication in the last 5 years regarding new ion-binding modes exhibited by valinomycin.

Perspectives

Dr. Megumi Fujita (Author)
University of West Georgia

I have been working on synthetic and natural ion receptors in the past 7 years, at a predominantly-undergraduate-institution kind of a pace. This work was made possible through the collaboration with Dr. John Bacsa, the director of Emory X-ray Crystallography Center. Thanks to Dr. Bacsa's comprehensive structural refinement and beautiful figures he generated, this work is making the cover page of the August issue of Acta Crystallographica Section C!

The following have contributed to this page: Dr. Megumi Fujita