title: On the mechanisms involved in biological heme crystallization.
abstract: Blood-feeding organisms digest hemoglobin, releasing large quantities of heme inside their digestive tracts. Free heme is very toxic, and these organisms have evolved several mechanisms to protect against its deleterious effects. One of these adaptations is the crystallization of heme into the dark-brown pigment hemozoin (Hz). Here we review the process of Hz formation, focusing on organisms other than Plasmodium that have contributed to a better understanding of heme crystallization. Hemozoin has been found in several distinct classes of organisms including protozoa, helminths and insects and Hz formation is the predominant form of heme detoxification. The available evidence indicates that amphiphilic structures such as phospholipid membranes and lipid droplets accompanied by specific proteins play a major role in heme crystallization. Because this process is specific to a number of blood-feeding organisms and absent in their hosts, Hz formation is an attractive target for the development of novel drugs to control illnesses associated with these hematophagous organisms.
authors.affiliation: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: Stiebler
authors.forename: Juliana B R Correa
authors.initials: JB
authors.lastname: Soares
authors.forename: Bruno L
authors.initials: BL
authors.lastname: Timm
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Silva
authors.forename: Flavia B
authors.initials: FB
authors.lastname: Mury
authors.forename: Marilvia
authors.initials: M
authors.lastname: Dansa-Petretski
authors.forename: Marcus F
authors.initials: MF
authors.lastname: Oliveira
mesh_terms: D000818:Animals; D003460:Crystallization; D041981:Gastrointestinal Tract / Q000378:metabolism; D006376:Helminths / Q000378:metabolism*; D006418:Heme / Q000378:metabolism* / Q000633:toxicity; D006420:Hemeproteins / Q000378:metabolism*; D010271:Parasites / Q000378:metabolism*; D010961:Plasmodium / Q000378:metabolism*; D014225:Triatominae / Q000378:metabolism*; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: D006420:Hemeproteins; C020753:hemozoin; D006418:Heme; D000520:alpha-Glucosidases