InterPro domain: IPR010048

Hybrid cluster proteins (HCP, or Prismane) have been identified in bacteria, archaea and eukaryotic protozoa. No specific function has yet been assigned to these proteins, but it may involve oxidoreductase enzymatic activity. These proteins contain one 4Fe-4S cluster, and one hybrid 4Fe-2O-2S cluster, the latter being similar to the Ni-Fe-S cluster found in carbon monoxide dehydrogenase enzymes ( IPR010047 ) [ 1 , 2 ].

This subfamily is heterogeneous with respect to the presence or absence of a region of about 100 amino acids not far from the N terminus of the protein. Members have been described as monomeric.The general function is unknown, although members from E. coli and several other species have hydroxylamine reductase activity. Members are found in various bacteria, in Archaea, and in several parasitic eukaryotes: Giardia intestinalis, Trichomonas vaginalis, and Entamoeba histolytica.

1. Reduced hybrid cluster proteins (HCP) from Desulfovibrio desulfuricans ATCC 27774 and Desulfovibrio vulgaris (Hildenborough): X-ray structures at high resolution using synchrotron radiation. J. Biol. Inorg. Chem. 8, 540-8
2. Structure of the hybrid cluster protein (HCP) from Desulfovibrio desulfuricans ATCC 27774 containing molecules in the oxidized and reduced states. Acta Crystallogr. D Biol. Crystallogr. 59, 2065-71