How helminth lipid-binding proteins offload their ligands to membranes: differential mechanisms of fatty acid transfer by the ABA-1 polyprotein allergen and Ov-FAR-1 proteins of nematodes and Sj-FABPc of schistosomes.
How helminth lipid-binding proteins offload their ligands to membranes: differential mechanisms of fatty acid transfer by the ABA-1 polyprotein allergen and Ov-FAR-1 proteins of nematodes and Sj-FABPc of schistosomes.
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蠕虫脂质结合蛋白如何将其配体卸载到膜上：线虫的 ABA-1 多蛋白过敏原和 Ov-FAR-1 蛋白以及血吸虫的 Sj-FABPc 脂肪酸转移的差异机制。
DOI：
10.1021/bi0159635
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发表时间：
2002
期刊：
影响因子：
2.9
通讯作者：
Storch,Judith
中科院分区：
文献类型：
--
作者：
McDermott,Lindsay;Kennedy,MalcolmW;McManus,DonaldP;Bradley,JanE;Cooper,Alan;Storch,Judith
在蠕虫寄生虫中发现了三种不同类型的小脂质结合蛋白（LBP）。虽然大小相似，但线虫的阿坝-1A 1（也称为As-NPA-A1）和Ov-FAR-1（以前称为Ov 20）蛋白主要是α-螺旋，在哺乳动物中没有已知的结构对应物，而线虫体的Sj-FABPc预计形成类似于哺乳动物细胞内脂肪酸结合蛋白家族的β-桶结构。产生这些蛋白质的寄生虫无法合成自己的复杂脂质，而是完全依赖于宿主的供应。作为阐明这些蠕虫蛋白质是否参与宿主脂质的获取的第一步，通过比较使用荧光共振能量转移测定从蛋白质到人工磷脂囊泡的配体转移的速率和机制，检查这些LBP将其配体递送到受体膜的过程。所有三种蛋白质结合荧光脂肪酸2-（9-anthrooxy）棕榈酸（2AP）类似，但有明显的差异，脂肪酸转移的速率和机制。Sj-FABPc显示碰撞机制; 2AP转移速率随着受体膜浓度的增加而增加，受受体膜电荷的调制，并且在盐浓度增加的情况下不会减少。相反，从Ov-FAR-1和阿坝-1A 1的配体的转移涉及水扩散步骤;从这些蛋白质的转移速率不受受体膜浓度或电荷的调节，但确实随着缓冲液的离子强度而降低。尽管有这些差异，所有的蛋白质直接与膜相互作用，使用cytochromeccompetition测定，虽然Sj-FABPc相互作用的程度比Ov-FAR-1或rABA-1A 1。总之，这些结果表明，Sj-FABPc最有可能参与脂肪酸的细胞内靶向转运和代谢，而Ov-FAR-1和阿坝-1A 1可能以类似于细胞外LBP如血清白蛋白和血浆视黄醇结合蛋白的方式表现。
Three different classes of small lipid-binding protein (LBP) are found in helminth parasites. Although of similar size, the ABA-1A1 (also designated As-NPA-A1) and Ov-FAR-1 (formerly known as Ov20) proteins of nematodes are mainly α-helical and have no known structural counterparts in mammals, whereas Sj-FABPc of schistosomes is predicted to form a β-barrel structure similar to the mammalian family of intracellular fatty acid binding proteins. The parasites that produce these proteins are unable to synthesize their own complex lipids and, instead, rely entirely upon their hosts for supply. As a first step in elucidating whether these helminth proteins are involved in the acquisition of host lipid, the process by which these LBPs deliver their ligands to acceptor membranes was examined, by comparing the rates and mechanisms of ligand transfer from the proteins to artificial phospholipid vesicles using a fluorescence resonance energy transfer assay. All three proteins bound the fluorescent fatty acid 2-(9-anthroyloxy)palmitic acid (2AP) similarly, but there were clear differences in the rates and mechanisms of fatty acid transfer. Sj-FABPc displayed a collisional mechanism; 2AP transfer rates increased with acceptor membrane concentration, were modulated by acceptor membrane charge, and were not diminished in the presence of increasing salt concentrations. In contrast, transfer of ligand from Ov-FAR-1 and ABA-1A1 involved an aqueous diffusion step; transfer rates from these proteins were not modulated by acceptor membrane concentration or charge but did decrease with the ionic strength of the buffer. Despite these differences, all of the proteins interacted directly with membranes, as determined using a cytochromeccompetition assay, although Sj-FABPc interacted to a greater extent than did Ov-FAR-1 or rABA-1A1. Together, these results suggest that Sj-FABPc is most likely to be involved in the intracellular targeted transport and metabolism of fatty acids, whereas Ov-FAR-1 and ABA-1A1 may behave in a manner analogous to that of extracellular LBPs such as serum albumin and plasma retinol binding protein.
寄生线虫：分子生物学、生物化学和免疫学。
DOI：
--
发表时间：
2002
期刊：
影响因子：
--
作者：
Rca Thompson
通讯作者：
Rca Thompson