Ehhmbp45 is a novel hemoglobin-binding protein identified in Entamoeba histolytica

Hemoglobin-binding proteins are necessary for pathogens to obtain iron from Hb. Entamoeba histolytica can grow using Hb as source of iron, but the underlying mechanism has not previously been established. In this work, we identified a 45kDa Hb-binding protein of E. histolytica, which we named Ehhmbp45. In silico analysis showed that Ehhmbp45 contains the conserved domains needed for Hb-binding, while overlay assays demonstrated that Ehhmbp45 is able to bind Hb. In addition, we found that Ehhmbp45 mRNA levels were up-regulated under iron starvation conditions and were subsequently restored to basal levels when Hb was added to the cell cultures. These findings provide the first insights on the role of Ehhmbp45 in iron acquisition from Hb.