title: Cloning and identification of a gene coding for a 26-kDa hemoglobin-binding protein from Entamoeba histolytica.
abstract: The capability of Entamoeba histolytica to use hemoglobin (Hb) as an iron source has been documented. However, the underlying mechanism to acquire iron from this source is poorly understood. In the present work, an in silico analysis in the E. histolytica genome (Pathema database) allowed us to identify a gene coding for a putative 26-kDa protein (Ehhmbp26) which contains the motifs necessary for Hb-binding. The purified Ehhmbp26 protein was able to bind Hb. Albeit with less efficiency, trophozoites were able to grow using Hb as the only iron source. In addition, ehhmbp26 RNA and the Ehhmbp26 protein were only expressed under iron restrictive conditions and ehhmbp26 RNA was subsequently inhibited after iron supplementation indicating that ehhmbp26 gene is negatively regulated by iron. These results suggest that the Ehhmbp26 protein may be involved in a mechanism by which E. histolytica scavenges iron from Hb.
authors.affiliation: Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, San Lorenzo 290, Col. Del Valle, C.P. 03100, México, D.F., México.
authors.forename: Areli
authors.initials: A
authors.lastname: Cruz-Castañeda
authors.forename: Javier
authors.initials: J
authors.lastname: Hernández-Sánchez
authors.forename: José J
authors.initials: JJ
authors.lastname: Olivares-Trejo
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003198:Computer Simulation; D030541:Databases, Genetic; D004748:Entamoeba histolytica / Q000235:genetics* / Q000378:metabolism; D017125:Genes, Protozoan; D005982:Glutathione Transferase / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011485:Protein Binding / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D002352:Carrier Proteins; D006454:Hemoglobins; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D005982:Glutathione Transferase