Synthetic Hemozoin (β-Hematin) Crystals Nucleate at the Surface of Neutral Lipid Droplets That Control Their Sizes
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Emulsions of monopalmitoylglycerol (MPG) and of a neutral lipid blend (NLB), consisting of MPG, monostearoylglycerol, dipalmitoylglycerol, dioleoylglycerol and dilineoylglycerol (4:2:1:1:1), the composition associated with hemozoin from the malaria parasite , have been used to mediate the formation of β-hematin microcrystals. Transmission electron microscopy (TEM), electron diffraction and electron spectroscopic imaging/electron energy loss spectroscopy (ESI/EELS) have been used to characterize both the lipid emulsion and β-hematin crystals. The latter have been compared with β-hematin formed at a pentanol/aqueous interface and with hemozoin both within parasites and extracted from the parasites. When lipid and ferriprotoporphyrin IX solutions in 1:9 v/v acetone/methanol were thoroughly pre-mixed either using an extruder or ultrasound, β-hematin crystals were found formed in intimate association with the lipid droplets. These crystals resembled hemozoin crystals, with prominent {100} faces. Lattice fringes in TEM indicated that these faces made contact with the lipid surface. The average length of these crystals was 0.62 times the average diameter of NLB droplets and their size distributions were statistically equivalent after 10 min incubation, suggesting that the lipid droplets also controlled the sizes of the crystals. This most closely resembles hemozoin formation in the helminth worm , while in , crystal formation appears to be associated with the much more gently curved digestive vacuole membrane which apparently leads to formation of much larger hemozoin crystals, similar to those formed at the flat pentanol-water interface.
Klar P, Waterman D, Gruene T, Mullick D, Song Y, Gilchrist J ACS Cent Sci. 2024; 10(8):1504-1514.
PMID: 39220700 PMC: 11363319. DOI: 10.1021/acscentsci.4c00162.
Lipid droplets of protozoan parasites: survival and pathogenicity.
Tavares V, Castro M, Souza R, Goncalves I, Berlink Lima J, de Matos Borges V Mem Inst Oswaldo Cruz. 2022; 116:e210270.
PMID: 35195194 PMC: 8851939. DOI: 10.1590/0074-02760210270.
Heme Detoxification in the Malaria Parasite: A Target for Antimalarial Drug Development.
de Villiers K, Egan T Acc Chem Res. 2021; 54(11):2649-2659.
PMID: 33982570 PMC: 8290263. DOI: 10.1021/acs.accounts.1c00154.
Ma W, Balta V, West R, Newlin K, Miljanic O, Sullivan D J Biol Chem. 2020; 296:100123.
PMID: 33239360 PMC: 7949059. DOI: 10.1074/jbc.RA120.016115.
Unsymmetrical Bisquinolines with High Potency against Malaria.
Liebman K, Burgess S, Gunsaru B, Kelly J, Li Y, Morrill W Molecules. 2020; 25(9).
PMID: 32397659 PMC: 7249153. DOI: 10.3390/molecules25092251.