Crystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particles

Simple item page
dc.contributor.authorHoang, Anh N
dc.contributor.authorNcokazi, Kanyile K
dc.contributor.authorde Villiers, Katherine A
dc.contributor.authorWright, David W
dc.contributor.authorEgan, Timothy J
dc.date.accessioned2016-07-22T13:04:23Z
dc.date.available2016-07-22T13:04:23Z
dc.date.issued2010
dc.date.updated2016-07-22T13:03:01Z
dc.description.abstractThe mechanism of formation of haemozoin, a detoxification by-product of several blood-feeding organisms including malaria parasites, has been a subject of debate; however, recent studies suggest that neutral lipids may serve as a catalyst. In this study, a model system consisting of an emulsion of neutral lipid particles was employed to investigate the formation of b-haematin, the synthetic counterpart of haemozoin, at the lipid–water interface. A solution of monoglyceride, either monostearoylglycerol (MSG) or monopalmitoylglycerol (MPG), dissolved in acetone and methanol was introduced to an aqueous surface. Fluorescence, confocal and transmission electron microscopic (TEM) imaging and dynamic light scattering analysis of samples obtained from beneath the surface confirmed the presence of homogeneous lipid particles existing in two major populations: one in the low micrometre size range and the other in the hundred nanometre range. The introduction of haem (Fe(III)PPIX) to this lipid particle system under biomimetic conditions (37 ◦C, pH 4.8) produced b-haematin with apparent first-order kinetics and an average half life of 0.5 min. TEM of monoglycerides (MSG or MPG) extruded through a 200 nm filter with haem produced b-haematin crystals aligned and parallel to the lipid–water interface. These TEM data, together with a model system replacing the lipid with an aqueous organic solvent interface using either methyl laurate or docosane demonstrated that the OH and C=O groups are apparently necessary for efficient nucleation. This suggests that b-haematin crystallizes via epitaxial nucleation at the lipid–water interface through interaction of Fe(III)PPIX with the polar head group. Once nucleated, the crystal grows parallel to the interface until growth is terminated by the curvature of the lipid particle. The hydrophobic nature of the mature crystal favours an interior transport resulting in crystals aligned parallel to the lipid–water interface and each other, strikingly similar to that seen in malaria parasites.en_ZA
dc.identifierhttp://dx.doi.org/10.1039/B914359A
dc.identifier.apacitationHoang, A. N., Ncokazi, K. K., de Villiers, K. A., Wright, D. W., & Egan, T. J. (2010). Crystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particles. <i>Dalton Transactions</i>, http://hdl.handle.net/11427/20598en_ZA
dc.identifier.chicagocitationHoang, Anh N, Kanyile K Ncokazi, Katherine A de Villiers, David W Wright, and Timothy J Egan "Crystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particles." <i>Dalton Transactions</i> (2010) http://hdl.handle.net/11427/20598en_ZA
dc.identifier.citationHoang, A. N., Ncokazi, K. K., de Villiers, K. A., Wright, D. W., & Egan, T. J. (2010). Crystallization of synthetic haemozoin (β-haematin) nucleated at the surface of lipid particles. Dalton Transactions, 39(5), 1235-1244.en_ZA
dc.identifier.issn1477-9226en_ZA
dc.identifier.ris TY - Journal Article AU - Hoang, Anh N AU - Ncokazi, Kanyile K AU - de Villiers, Katherine A AU - Wright, David W AU - Egan, Timothy J AB - The mechanism of formation of haemozoin, a detoxification by-product of several blood-feeding organisms including malaria parasites, has been a subject of debate; however, recent studies suggest that neutral lipids may serve as a catalyst. In this study, a model system consisting of an emulsion of neutral lipid particles was employed to investigate the formation of b-haematin, the synthetic counterpart of haemozoin, at the lipid–water interface. A solution of monoglyceride, either monostearoylglycerol (MSG) or monopalmitoylglycerol (MPG), dissolved in acetone and methanol was introduced to an aqueous surface. Fluorescence, confocal and transmission electron microscopic (TEM) imaging and dynamic light scattering analysis of samples obtained from beneath the surface confirmed the presence of homogeneous lipid particles existing in two major populations: one in the low micrometre size range and the other in the hundred nanometre range. The introduction of haem (Fe(III)PPIX) to this lipid particle system under biomimetic conditions (37 ◦C, pH 4.8) produced b-haematin with apparent first-order kinetics and an average half life of 0.5 min. TEM of monoglycerides (MSG or MPG) extruded through a 200 nm filter with haem produced b-haematin crystals aligned and parallel to the lipid–water interface. These TEM data, together with a model system replacing the lipid with an aqueous organic solvent interface using either methyl laurate or docosane demonstrated that the OH and C=O groups are apparently necessary for efficient nucleation. This suggests that b-haematin crystallizes via epitaxial nucleation at the lipid–water interface through interaction of Fe(III)PPIX with the polar head group. Once nucleated, the crystal grows parallel to the interface until growth is terminated by the curvature of the lipid particle. The hydrophobic nature of the mature crystal favours an interior transport resulting in crystals aligned parallel to the lipid–water interface and each other, strikingly similar to that seen in malaria parasites. DA - 2010 DB - OpenUCT DP - University of Cape Town J1 - Dalton Transactions LK - https://open.uct.ac.za PB - University of Cape Town PY - 2010 SM - 1477-9226 T1 - Crystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particles TI - Crystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particles UR - http://hdl.handle.net/11427/20598 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/20598
dc.identifier.urihttp://pubs.rsc.org/en/content/articlelanding/2010/dt/b914359a#!divAbstract
dc.identifier.vancouvercitationHoang AN, Ncokazi KK, de Villiers KA, Wright DW, Egan TJ. Crystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particles. Dalton Transactions. 2010; http://hdl.handle.net/11427/20598.en_ZA
dc.languageengen_ZA
dc.publisherRoyal Society of Chemistryen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.sourceDalton Transactionsen_ZA
dc.source.urihttp://pubs.rsc.org/en/Journals/JournalIssues/DT#!recentarticles&adv
dc.subject.othersynthetic haemozoin
dc.titleCrystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particlesen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Hoang_Crystallization_synthetic_2010.pdf
Size:
614.29 KB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.72 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Journal Articles