title: Detergent-Mediated Formation of β-Hematin: Heme Crystallization Promoted by Detergents Implicates Nanostructure Formation for Use as a Biological Mimic.
abstract: Hemozoin is a unique biomineral that results from the sequestration of toxic free heme liberated as a consequence of hemoglobin degradation in the malaria parasite. Synthetic neutral lipid droplets (SNLDs) and phospholipids were previously shown to support the rapid formation of β-hematin, abiological hemozoin, under physiologically relevant pH and temperature, though the mechanism by which heme crystallization occurs remains unclear. Detergents are particularly interesting as a template because they are amphiphilic molecules that spontaneously organize into nanostructures and have been previously shown to mediate β-hematin formation. Here, 11 detergents were investigated to elucidate the physicochemical properties that best recapitulate crystal formation in the parasite. A strong correlation between the detergent's molecular structure and the corresponding kinetics of β-hematin formation was observed, where higher molecular weight polar chains promoted faster reactions. The larger hydrophilic chains correlated to the detergent's ability to rapidly sequester heme into the lipophilic core, allowing for crystal nucleation to occur. The data presented here suggest that detergent nanostructures promote β-hematin formation in a similar manner to SNLDs and phospholipids. Through understanding mediator properties that promote optimal crystal formation, we are able to establish an in vitro assay to probe this drug target pathway.
authors.affiliation: Department of Chemistry, Vanderbilt University , Nashville, Tennessee, United States.
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Sandlin
authors.affiliation: Department of Chemistry, Vanderbilt University , Nashville, Tennessee, United States.
authors.forename: Kim Y
authors.initials: KY
authors.lastname: Fong
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States; Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: Stiebler
authors.affiliation: Department of Chemistry, Vanderbilt University , Nashville, Tennessee, United States.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Gulka
authors.affiliation: Department of Chemistry, Vanderbilt University , Nashville, Tennessee, United States.
authors.forename: Jenny E
authors.initials: JE
authors.lastname: Nesbitt
authors.affiliation: Laboratório de Bioquímica de Resposta ao Estresse, Programa de Biologia Molecular e Biotecnologia, Instituto de Bioquímica Médica, Leopoldo de Meis, Universidade Federal do Rio de Janeiro , Rio de Janeiro, RJ, Brazil.
authors.forename: Matheus P
authors.initials: MP
authors.lastname: Oliveira
authors.affiliation: Laboratório de Bioquímica de Resposta ao Estresse, Programa de Biologia Molecular e Biotecnologia, Instituto de Bioquímica Médica, Leopoldo de Meis, Universidade Federal do Rio de Janeiro , Rio de Janeiro, RJ, Brazil.
authors.forename: Marcus F
authors.initials: MF
authors.lastname: Oliveira
authors.affiliation: Department of Chemistry, Vanderbilt University , Nashville, Tennessee, United States.
authors.forename: David W
authors.initials: DW
authors.lastname: Wright