Iron is an essential nutrient required by pathogens to survive and proliferate in the host environment. Host heme represents one viable iron source for bacterial pathogens, which have evolved diverse heme degradation pathways to acquire iron, in both aerobic and anaerobic environments. ChuW catalyzes anaerobic heme degradation in Escherichia coli O157:H7, converting the porphyrin substrate into the linear tetrapyrrole product termed anaerobilin and liberating iron. Although ChuW is an established anaerobic heme degrader, further mechanistic investigation is required, and the role of adjacent heme utilization proteins in the degradation process require further investigation. Here, we provide evidence for a heme-iron independent porphyrin ring-opening mechanism, as well provide evidence for other E. coli heme utilization proteins acting as heme and anaerobilin chaperones during catalysis.