RESUMEN
The same anthocyanin pigment makes roses red but cornflowers blue, a phenomenon that has so far not been entirely explained. Here we describe the X-ray crystal structure of the cornflower pigment, which reveals that its blue colour arises from a complex of six molecules each of anthocyanin and flavone, with one ferric iron, one magnesium and two calcium ions. We believe that this tetrametal complex may represent a previously undiscovered type of supermolecular pigment.
Asunto(s)
Antocianinas/química , Centaurea/química , Flores/química , Pigmentación , Antocianinas/metabolismo , Cationes/metabolismo , Color , Cristalografía por Rayos X , Metales/metabolismo , Modelos Moleculares , Conformación Molecular , Rosa/químicaRESUMEN
The X-ray crystal structure of natural commelinin is investigated. The results demonstrate that commelinin is a tetranuclear (4 Mg(2+)) metal complex, in which two Mg(2+) ions chelate to six anthocyanin molecules, while the other two Mg(2+) ions bind to six flavone molecules, stabilizing the commelinin complex, a new type of supramolecular complex.