Iron-coproporphyrin III is a natural cofactor in bacterioferritin from theanaerobic bacterium Desulfovibrio desulfuricans

A bacterioferritin was recently isolated from the anaerobic sulphate-reduci ng bacterium Desulfovibrio desulfuricans ATCC 27774 [Romao et al, (2000) Bi ochemistry 39, 6841-6849]. Although its properties are in general similar t o those of the other bacterioferritins, it contains a haem quite distinct f rom the haem B, found in bacterioferritins from aerobic organisms. Using vi sible and NMR spectroscopies, as well as mass spectrometry analysis, the ha em is now unambiguously identified as iron-coproporphyrin III, the first ex ample of such a prosthetic group in a biological system, This unexpected fi nding is discussed in the framework of haem biosynthetic pathways in anaero bes and particularly in sulphate-reducing bacteria. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V, All righ ts reserved.