Hemin-binding surface protein from Bartonella quintana
Hemin-binding surface protein from Bartonella quintana
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DOI：
10.1128/iai.68.12.6750-6757.2000
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发表时间：
2000-12-01
影响因子：
3.1
通讯作者：
Minnick, MF
中科院分区：
文献类型：
--
作者：
Carroll, JA;Coleman, SA;Minnick, MF
五日巴尔通体是战壕热的病原体，也是人类心内膜炎和细菌性血管瘤病的一种病因，据报道，它对任何细菌的体外氯化血红素需求量最高。我们确定了来自B. quintana与氯化血红素结合，与25-kDa蛋白（HbpA）相似的蛋白是氯化血红素的优势结合蛋白。像许多外膜蛋白一样，HbpA分配到细胞的Triton X-114提取物的去污剂相，并且是热可修饰的，当在100 ℃溶解时显示出从约25至30 kDa的表观分子量变化。纯化的外膜和内膜的免疫印迹和免疫电镜与全细胞显示，HbpA严格位于外膜和表面暴露，分别。确定成熟HbpA的N-末端序列并用于从λ基因组文库中克隆HbpA编码基因（hbpA）。hbpA基因的长度为816 bp，编码预测的约29.3 kDa的未成熟蛋白和27.1 kDa的成熟蛋白。与大肠杆菌Fur共有序列具有53%同一性的Fur盒同源物位于hbpA的上游，并且可能参与调节表达。BLAST检索表明，与HbpA最接近的同源物包括汉赛巴尔通体噬菌体相关膜蛋白Pap31（58.4%同一性）和来自羊种布鲁氏菌的OMP31孔蛋白（31.7%同一性）。高严格性Southern印迹表明，所有五种致病性巴尔通体属。具有hbpA同源物。重组HbpA在体外能与氯化血红素结合，但在E.杆菌完整的B。用纯化的抗-HbpA Fab片段处理的quintana相对于对照显示出血晶素结合的显著（P <0.004）剂量依赖性降低，表明HbpA在血晶素获得中起积极作用，因此在发病机制中起积极作用。HbpA是从B中发现的第一个潜在的毒力决定因子。quintana。
Bartonella quintana, the agent of trench fever and a cause of endocarditis and bacillary angiomatosis in humans, has the highest reported in vitro hemin requirement for any bacterium. We determined that eight membrane-associated proteins from B. quintana bind hemin and that a similar to 25-kDa protein (HbpA) was the dominant hemin binding protein. Like many outer membrane proteins, HbpA partitions to the detergent phase of a Triton X-114 extract of the cell and is heat modifiable, displaying an apparent molecular mass shift from approximately 25 to 30 kDa when solubilized at 100 degreesC. Immunoblots of purified outer and inner membranes and immunoelectron microscopy with whole cells show that HbpA is strictly located in the outer membrane and surface exposed, respectively. The N-terminal sequence of mature HbpA was determined and used to clone the HbpA-encoding gene (hbpA) from a lambda genomic library. The hbpA gene is 816 bp in length, encoding a predicted immature protein of approximately 29.3 kDa and a mature protein of 27.1 kDa. A Fur box homolog with 53% identity to the Escherichia coli Fur consensus is located upstream of hbpA and may be involved in regulating expression. BLAST searches indicate that the closest homologs to HbpA include the Bartonella henselae phage associated membrane protein, Pap31 (58.4% identity), and the OMP31 porin from Brucella melitensis (31.7% identity). High-stringency Southern blots indicate that all five pathogenic Bartonella spp. possess hbpA homologs. Recombinant HbpA can bind hemin in vitro; however, it does not confer a hemin-binding phenotype upon E. coli. Intact B. quintana treated with purified anti-HbpA Fab fragments show a significant (P < 0.004) dose-dependent decrease in hemin binding relative to controls, suggesting that HbpA plays an active role in hemin acquisition and therefore pathogenesis. HbpA is the first potential virulence determinant characterized from B. quintana.