Figure 3. Schematic diagram of the general architecture of the beta-alpha subunit fusion nitrile hydratase found in eukaryotes.

This form is known to be found in M. brevicollis, S. rosetta, S. diplocostata, S. arctica, T. trahens, A. anophagefferens, F. cylindrus, B. natans and E. huxleyi. The red area denotes the beta subunit, which is located N-terminally of the alpha subunit (green region). The CTLCSC active site is located in the alpha subunit, as shown by the shaded area. The yellow area denotes the histidine-rich stretch found between the subunit domains in opisthokonts.