Genetic and biochemical analysis of erythrocyte-stage surface antigens belonging to a family of highly conserved proteins of Babesia equi and Theileria species
Genetic and biochemical analysis of erythrocyte-stage surface antigens belonging to a family of highly conserved proteins of Babesia equi and Theileria species
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DOI：
10.1016/s0166-6851(97)00150-3
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发表时间：
1997-12-01
影响因子：
1.5
通讯作者：
Perryman, LE
中科院分区：
文献类型：
--
作者：
Knowles, DP;Kappmeyer, LS;Perryman, LE
马巴贝斯虫红细胞期表达一种34 kda的免疫优势抗原，可被世界范围内持续感染马的抗体识别。这种红细胞期表面蛋白马胚子抗原-1 （equi merozoite antigen-1, EMA-1）由一个单拷贝基因编码，先前的研究表明，它与瑟氏梭菌和布氏梭菌的相似大小的蛋白具有33%的氨基酸同源性。parve T.， T. annulata和T. mutans相似大小的蛋白质平均同源性为31%。克隆了另一个马双头马的基因ema2的基因组拷贝和cDNA拷贝。单拷贝ema2基因编码一个30 kda的蛋白（EMA-2），该蛋白与EMA-1具有52%的氨基酸同源性。EMA-2与希勒菌中具有相似分子质量的蛋白质的氨基酸同源性平均为31%。ema - 1和EMA-2都含有一个糖基磷脂酰肌醇锚点。这些独特的红细胞期表面蛋白缺乏抗原重复序列，不包括信号肽，含有一个或不含半胱氨酸。与该家族蛋白与红细胞表面相互作用的假设相一致，t种蛋白具有基本的等电点。马b蛋白具有酸性等电点，但其中的24-mer肽具有强碱性净电荷。(C) 1997爱思唯尔科学有限公司
Erythrocyte-stage Babesia equi expresses a 34-kDa immunodominant antigen recognized by antibody from persistently infected horses worldwide. This erythrocyte-stage surface protein, equi merozoite antigen-1 (EMA-1) is encoded by a single copy gene, and was previously shown to share 33% amino acid identity with similar sized proteins of Theileria sergenti and T. buffeli. A mean homology of 31% amino acid identity extends to similar sized proteins of T. parve, T. annulata and T. mutans. Genomic and cDNA copies of a second B. equi gene, ema2 were cloned. The single copy ema2 gene encodes a 30-kDa protein (EMA-2) that shares 52% amino acid identity with EMA-1. EMA-2 also shares a mean amino acid identity of 31% with proteins of similar molecular mass from Theileria species. EMA-I and EMA-2 each contain a glycosylphosphatidylinositol anchor. These unique erythrocyte-stage surface proteins of B. equi and Theileria species lack antigenic repeats, and excluding the signal peptide, contain one or no cysteines. Consistent with the hypothesis that this family of proteins interacts with the erythrocyte surface, the T. species proteins possess a basic isoelectric point. The B. equi proteins have acidic isoelectric points, but 24-mer peptides within them have strongly basic net charges. (C) 1997 Elsevier Science B.V.