FERRICHROME IRON-FREE FROM USTILAGO;ferrichrome iron-free from ustilago*sphaerogena;Cyclo[glycyl-N5-[(2E)-4-carboxy-3-methyl-1-oxo-2-buten-1-yl]-N5-hydroxy-L-ornithyl-N5-[(2E)-4-carboxy-3-methyl-1-oxo-2-buten-1-yl]-N5-hydroxy-L-ornithyl-N5-[(2E)-4-carboxy-3-methyl-1-oxo-2-buten-1-yl]-N5-hydroxy-L-ornithyl-L-seryl-L-seryl]