Identification of the immunodominant protein and other proteins of the Bacillus anthracis exosporium
Identification of the immunodominant protein and other proteins of the Bacillus anthracis exosporium
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DOI：
10.1128/jb.185.6.1903-1910.2003
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发表时间：
2003-03-01
影响因子：
3.2
通讯作者：
Turnbough, CL
中科院分区：
文献类型：
--
作者：
Steichen, C;Chen, P;Turnbough, CL
炭疽的病原体炭疽芽孢杆菌的孢子被一个突出的松散的、气球状的层包裹着，叫做外孢子。虽然外孢子是孢子表面抗原的来源和主要的渗透性屏障，但其分子结构和功能尚不清楚。在本研究中，我们鉴定了纯化的炭疽芽胞杆菌（Sterne菌株）外孢子菌中的5种主要蛋白。其中一种蛋白质是最近发现的胶原样糖蛋白BclA，它似乎是外孢子毛状绒毛的结构成分。利用大量独特的抗孢子单克隆抗体，我们证明了BclA是炭疽芽孢杆菌孢子表面的免疫优势抗原。我们还表明，BctA蛋白而不是碳水化合物成分主导了主要的免疫反应。另外，中央的长度（GXX）。BctA的重复区似乎是菌株特异性的。另外两个独特的蛋白，BxpA和BxpB也被鉴定出来。BxpA含有异常丰富的Gin和Pro残基，并包含几个不同的串联重复序列，这些重复序列也表现出菌株特异性差异。此外，BxpA被发现被切割成大约两半。BxpB似乎是糖基化的或与糖基化物质相关，并由一个基因编码，该基因（与bclA一起）可能是外孢子基因组岛的一部分。鉴定出的另外两种蛋白质是丙氨酸消旋酶和超氧化物歧化酶，这两种蛋白质都与其他芽孢杆菌孢子的表面有关。讨论了新鉴定蛋白的可能功能。
Spores of Bacillus anthracis, the causative agent of anthrax, are enclosed by a prominent loose-fitting, balloon-like layer called the exosporium. Although the exosporium serves as the source of surface antigens and a primary permeability barrier of the spore, its molecular structure and function are not well characterized. In this study, we identified five major proteins in purified B. anthracis (Sterne strain) exosporia. One protein was the recently identified collagen-like glycoprotein BclA, which appears to be a structural component of the exosporium hair-like nap. Using a large panel of unique antispore monoclonal antibodies, we demonstrated that BclA is the immunodominant antigen on the B. anthracis spore surface. We also showed that the BctA protein and not a carbohydrate constituent directs the dominant immune response. In addition, the length of the central (GXX). repeat region of BctA appears to be strain specific. Two other unique proteins, BxpA and BxpB, were identified. BxpA is unusually rich in Gin and Pro residues and contains several different tandem repeats, which also exhibit strain-specific variation. In addition, BxpA was found to be cleaved approximately in half. BxpB appears to be glycosylated or associated with glycosylated material and is encoded by a gene that (along with bclA) may be part of an exosporium genomic island. The other two proteins identified were alanine racemase and superoxide dismutase, both of which were reported to be associated with the surface of other Bacillus spores. Possible functions of the newly identified proteins are discussed.