Plasmodium vivax merozoite surface protein-3 contains coiled-coil motifs in an alanine-rich central domain
Plasmodium vivax merozoite surface protein-3 contains coiled-coil motifs in an alanine-rich central domain
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DOI：
10.1016/s0166-6851(99)00063-8
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发表时间：
1999-06-25
影响因子：
1.5
通讯作者：
Barnwell, JW
中科院分区：
文献类型：
--
作者：
Galinski, MR;Corredor-Medina, C;Barnwell, JW
疟原虫裂殖子表面覆盖着一层栅栏状蛋白质层，这些蛋白质层排列成有组织的束或在电子显微镜下看起来像突出的刺突。在这里，我们提出了第三间日疟原虫裂殖子表面蛋白，PvMSP-3，这是相关的，但不锚定在裂殖子膜。使用来自间日疟原虫免疫松鼠猴的血清来筛选λ gt 11间日疟原虫基因组DNA（gDNA）文库。来自克隆号6.1的噬斑选择性抗体和针对其编码蛋白的兔抗血清在免疫荧光测定（IFA）中产生了与在成熟裂殖子和游离裂殖子表面的定位一致的模式。特异性抗血清也凝集裂殖子，并通过SDS-PAGE识别150 000 Da的蛋白。完整的msp-3基因和侧翼序列从间日疟原虫λ Dash II gDNA文库中克隆，并且还通过RACE（cDNA末端的快速扩增）进行部分表征。紧邻上游序列包含非编码重复序列和推定的蛋白质编码开放阅读框（ORF），其也存在于msp-3 5 'RACE基因产物上。Pvmsp-3编码的蛋白质的计算质量为89 573 Da，它有一个潜在的信号肽和一个主要的中央丙氨酸丰富的结构域（31%），表现出很大程度上的α-螺旋二级结构和两侧的带电区域。该蛋白不具有推定的跨膜结构域或糖基磷脂酰肌醇（GPI）锚修饰的共有序列。然而，富含丙氨酸的结构域具有七肽重复序列，预测其形成卷曲螺旋三级结构，其介导蛋白质-蛋白质相互作用。PvMSP-3在结构上与恶性疟原虫MSP-3和诺氏疟原虫的140 000 Da MSP相关。因此，PvMSP-3的表征也开始定义一个新的进化相关的疟原虫裂殖子蛋白的种间家族。(C)1999年由Elsevier Science B. V.出版，版权所有。
Plasmodium merozoites are covered with a palisade layer of proteins that are arranged as organized bundles or appear as protruding spikes by electron microscopy. Here we present a third Plasmodium vivax merozoite surface protein, PvMSP-3, which is associated with but not anchored in the merozoite membrane. Serum from a P, vivax immune squirrel monkey was used to screen a lambda gt11 P, vivax genomic DNA (gDNA) library. Plaque-selected antibodies from clone no. 6.1, and rabbit antisera against its encoded protein, produced a pattern in immunofluorescence assays (IFAs) that is consistent with a localization at the surface of mature schizonts and free merozoites. Specific antisera also agglutinated merozoites and recognized a protein of 150 000 Da by SDS-PAGE. The complete msp-3 gene and flanking sequences were cloned from a P. vivax lambda Dash II gDNA library and also partly characterized by RACE (rapid amplification of cDNA ends). The immediate upstream sequence contains non-coding repeats and a putative protein-encoding open reading frame (ORF), which are also present on the msp-3 5'RACE gene product. Pvmsp-3 encodes a protein with a calculated mass of 89 573 Da, which has a potential signal peptide and a major central alanine-rich domain (31%) that exhibits largely alpha-helical secondary structure and is flanked by charged regions. The protein does not have a putative transmembrane domain or a consensus sequence for a glycosylphosphatidylinositol (GPI) anchor modification. However, the alanine-rich domain has heptad repeats that are predicted to form coiled-coil tertiary structures, which mediate protein-protein interactions. PvMSP-3 is structurally related to P. falciparum MSP-3 and the 140 000 Da MSP of P, knowlesi. Characterization of PvMSP-3, thus, also begins to define a new interspecies family of evolutionarily related Plasmodium merozoite proteins. (C) 1999 Published by Elsevier Science B.V. All rights reserved.