Figure 1.
Schematic tree diagram of the eukaryotic supergroups showing the location of nitrile hydratase containing taxa.
After Walker et al. (2011). Groups labelled in black encompass the taxa listed in table S1; those in grey encompass the taxa in the EMBL/Genbank dbEST, and non-redundant protein and nucleotide databases. Blue = Opisthokonta, Brown = Amoebozoa, Magenta = Excavata, Green = Archaeplastida, Grey = CCTH Supergroup Red = SAR Supergroup, with stramenopile, alveolate and rhizarian labeled. Taxa in capitals contain multicellular species. Taxa highlighted contain species with nitrile hydratase genes. * = eukaryotic-type nitrile hydratase. Number of * indicates the number of subunits present. # = nitrile hydratase subunit genes that may be the result of prokaryotic contamination. Note that taxa branching from a single point represent nodes with ambiguous branching, and the eukaryotic tree is unrooted.
Figure 2.
Phylogenetic tree of the concatenated dataset of alpha, beta and fusion nitrile hydratase proteins.
The tree was produced using maximum likelihood with the WAG+G+F+I model from an alignment of 658 positions. Numbers at nodes are bootstrap support percentages from PhyML (1000 replicates)/RaxML (100 replicates). Bootstrap values <70 are shown as *. The scale bar indicates the average number of amino acid substitutions per site. Eukaryotic Key: Opisthokonta = blue SAR = red CCTH = grey Amoebozoa = brown Archaeplastida = Green. Prokaryotic Key: Actinobacteria = Magenta Cyanobacteria = Light Green Firmicutes = Purple Proteobacteria = Orange.
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.