Genetic and functional analysis of Haemophilus somnus high molecular weight-immunoglobulin binding proteins
Genetic and functional analysis of Haemophilus somnus high molecular weight-immunoglobulin binding proteins
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DOI：
10.1016/j.micpath.2005.08.002
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发表时间：
2005-11-01
影响因子：
3.8
通讯作者：
Corbeil, LB
中科院分区：
文献类型：
--
作者：
Tagawa, Y;Sanders, JD;Corbeil, LB
嗜血杆菌免疫球蛋白结合蛋白(IgBP)是与毒力相关的蛋白，但只有一个(P76)已被基因定义。我们测定了P76基因5‘侧翼区的核苷酸序列。该区域已被确定为一系列高分子量(HMW)-IgBPs的编码区。核苷酸序列分析表明，编码HMW和P76 IgBPs的基因(免疫球蛋白结合蛋白A，ibpA)由12,285个碱基对(BP)组成。IbpA基因两侧有一个1758bp的上游开放阅读框，命名为ibpB。预测的这两个基因的氨基酸序列与毒力外源蛋白及其转运蛋白相似，后者构成了各种革兰氏阴性菌中的两个伙伴分泌途径。序列中还鉴定了与哺乳动物细胞结合相关的基序。竞争性抑制研究表明，牛内皮细胞与肝素结合区存在粘附性。谷胱甘肽S转移酶融合片段的表达载体覆盖了972-3201个氨基酸残基。IgG2 Fc结合研究证实，片段972-1515(GST-IbpA3)为Fc结合肽。该多肽与GST-IbpA5(AA 2071-2730)能与恢复期血清发生强烈反应。在一项小规模的初步研究中，用纯化的GST-lbpA3多肽免疫的小牛可以抵抗支气管内嗜睡虫的攻击。(C)2005爱思唯尔有限公司。保留所有权利。
Haemophilus somnus immunoglobulin binding proteins (IgBPs) are virulence associated but only one (p76) has been genetically defined. We determined the nucleotide sequence of the 5'-flanking region of the p76 gene. This region had been identified as the coding region for a series of high molecular weight (HMW)-IgBPs. Analysis of the nucleotide sequence indicated the gene (immunoglobulin binding protein A, ibpA) encoding the HMW and p76 IgBPs comprised a single open reading frame of 12,285 base pairs (bp). The ibpA gene is flanked by an upstream ORF of 1758 bp, designated ibpB. The predicted amino acid sequences of these two genes demonstrate similarity to virulence exoproteins and their transporter proteins that comprise a two-partner secretion pathway in various Gram-negative bacteria. Motifs associated with binding to mammalian cells were also identified within the sequence. Competitive inhibition studies implicated a putative heparin-binding domain in adherence to bovine endothelial cells. Expression plasmids for glutathione S-transferase (GST)-fused recombinant fragments covered amino acid residues 972-3201. IgG2 Fc binding studies identified fragment 972-1515 (GST-IbpA3) as an Fc binding peptide. This peptide and GST-IbpA5 (aa 2071-2730) reacted strongly with convalescent phase serum. In a small preliminary study, calves immunized with the purified GST-lbpA3 peptide were protected against an intrabronchial H. somnus challenge. (C) 2005 Elsevier Ltd. All rights reserved.