1 ER2 Fe4s4 1.000 2 F3S Fe3-s4 cluster 0.875 3 F4S Fe4-s3 cluster 0.875 4 SF3 Fe4-s3 cluster 0.875 5 9S8 Non-cubane [4Fe-4S]-cluster 0.778 6 MSK Broken Fe4S4 cluster 0.778 7 S3F Oxidized [fe4-s3] cluster 0.778 8 SF4 Iron/sulfur cluster 0.778 9 WCC Fe(3)-ni(1)-S(4) cluster 0.778 10 ZKP Fe3-s4 methylated cluster 0.778 11 8JU Fe4-s4-O cluster 0.700 12 CUV Fe(4)-ni(1)-S(4) cluster, oxidized 0.700 13 Q46 Fe4 H s5 0.700 14 RQM Fe(3)-ni(1)-S(4) cluster 0.700 15 XCC Fe(4)-ni(1)-S(4) cluster 0.700