This protein has both 3-fold and 2-fold rotational axes of symmetry. The dimers are colored blue/cyan, yellow/orange, and violet/magenta.

Schindelin, H., Liu, M. T. W., Wuebbens, M. M., Rajagopalan, K. V.: Insights Into Molybdenum Cofactor Deficiency Provided by the Crystal Structure of the Molybdenum Cofactor Biosynthesis Protein Moac Structure (London) 8 pp. 709 (2000) (PubMed)

1ekr (PDB)  

   heptamer