Catalyzes the ferredoxin-dependent oxidative decarboxylation of arylpyruvates. CoA + indole-3-pyruvate + 2 oxidized [2Fe-2S]-[ferredoxin] = (indol-3-yl)acetyl-CoA + CO2 + H(+) + 2 reduced [2Fe-2S]-[ferredoxin] Binds 2 [4Fe-4S] clusters. In this family the first cluster has a non-standard and varying [4Fe-4S] binding motif CX(2)CX(2)CX(4-5)CP. Optimum temperature is 70 degrees Celsius. Heterodimer of the IorA and IorB subunits.