Figure 5

Iron-dependent dehydrogenase SIMBAL heat map and related structure. Panel A shows the SIMBAL heat map for Dtox_4270, a 419-residue group III iron-dependent dehydrogenase from Desulfotomaculum acetoxidans DSM 771. The training set contains 62 sequences in the TRUE partition and 1555 in the FALSE partition. This heat map shows a plume rising from a short subsequence TSNPKDYE, homologous to the sequence VPNPTITV in the sequence of lactaldehyde:1,2-propanediol oxidoreductase Of Escherichia Coli, which has a solved crystal structure 2BL4. Panel B shows the secondary structure cartoon of 2BL4 in green. The NAD cofactor is shown as space-filling spheres in yellow, and the iron atom as a blue sphere. The sequence identified by homology to the SIMBAL hot spot from panel A is shown in red, making close contact with the NAD but not with the iron atom. The location of the hot spot is consistent with a role in controlling the ability of NAD to exchange electrons to other redox carriers.