Oriented Nucleation of β-Hematin Crystals Induced at Various Interfaces: Relevance to Hemozoin Formation
Oriented Nucleation of β-Hematin Crystals Induced at Various Interfaces: Relevance to Hemozoin Formation
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DOI：
10.1021/cg8009755
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发表时间：
2009-01-01
影响因子：
3.8
通讯作者：
Leiserowitz, Leslie
中科院分区：
文献类型：
--
作者：
de Villiers, Katherine A.;Osipova, Maria;Leiserowitz, Leslie
脂质分子可以促进疟疾色素（疟原虫色素）和β-血红素晶体（合成疟原虫色素）的成核。为了确定 1-肉豆蔻酰甘油 (MMG) 成核的 β-血红素晶体在水面上的取向，我们进行了掠入射同步加速器 X 射线衍射和 X 射线反射率研究。我们的结果表明，预混合α-血红素与MMG产生了{100}面平行于水面取向的β-血红素纳米晶体，我们解释说，铺展溶液允许MMG分子聚集成暴露OH基团和与血红素分子相互作用的氧孤对电子的簇。血红素分子不与 MMG 簇相互作用，不会产生 β-血红素，而是产生未知的晶相。独立地，有证据表明，暴露 OH 基团的自组装功能化烷硫醇单层 (SAM) 主要通过其 {100} 面诱导 β-血红素成核，而暴露 CH3 的自组装功能化烷硫醇单层 (SAM) 则诱导 {100} 或 {010} 面成核，优先是 {010}。结果可以用 SAM 对这两个晶面的亲和力差异来解释。在不同条件下进行的两组 β-血红素成核实验强化了这样的观点：模拟消化液泡脂质表面的 MMG 分子通过立体特异性相互作用诱导 β-血红素在 {100} 面上定向成核。
The nucleation of malaria pigment (hemozoin) and beta-hematin crystals (synthetic hemozoin) can be promoted by lipid molecules. To determine the orientation of beta-hematin crystals nucleated by 1-myristoyl-glycerol (MMG) on the water surface, we undertook a grazing incidence synchrotron X-ray diffraction and X-ray reflectivity study. Our results indicate that premixed alpha-hematin with MMG yielded beta-hematin nanocrystals oriented with the {100} face parallel to water surface, which we explain insofar that the spreading solution allows MMG molecular aggregation into clusters exposing OH groups and oxygen lone-pair electrons that interact with hematin molecules. Hematin molecules, which did not interact with MMG clusters, do not yield beta-hematin, but rather an unknown crystalline phase. Independently, evidence is presented that self-assembled functionalized alkanethiol monolayers (SAMs) exposing OH groups induce beta-hematin nucleation primarily via its {100} face, whereas those exposing CH3 induce nucleation of either the {100} or {010} face, preferentially {010}. The results can be explained in terms of a difference in affinity of the SAMs to these two crystal faces. The two sets of beta-hematin nucleation experiments, conducted under different conditions, strengthen the notion that MMG molecules, mimicking a digestive vacuole lipid surface, induce, via stereospecific interactions, oriented nucleation of beta-hematin at the {100} face.