Iron(III) mesoporphyrin IX and iron(III) deuteroporphyrin IX bind to the Porphyromonas gingivalis HmuY hemophore

► Porphyromonas gingivalis HmuY binds mesoheme and deuteroheme in a fully analogous way to protoheme. ► HmuY-deuteroheme exists in two forms differing by a 180 porphyrin rotation. ► Our results clarify the bases of heme uptake in P. gingivalis. ► Our data may lead to development of novel anti-microbial therapeutics.