Five-member gene family of Bartonella quintana.
Five-member gene family of Bartonella quintana.
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金塔巴尔通体的五成员基因家族。
DOI：
10.1128/iai.71.2.814-821.2003
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发表时间：
2003
影响因子：
3.1
通讯作者：
Carroll,JamesA
中科院分区：
文献类型：
--
作者：
Minnick,MichaelF;Sappington,KateN;Smitherman,LauraS;Andersson,SivGE;Karlberg,Olof;Carroll,JamesA
五日巴尔通体是战壕热的病原体和杆菌性血管瘤病的病原体，与其他细菌病原体相比，其生长对氯化血红素的需求非常高。我们以前确定的主要氯化血红素受体的病原体作为一个30 kDa的表面蛋白，称为HbpA。本报告描述了另外四个与hbpA共享约48%氨基酸序列同一性的同源物。其中三个基因形成一个连锁簇，命名为hbpCAB，而其他成员hbpD和hbpE是不连锁的。二级结构预测和其他证据表明，Hbp家族成员是位于外膜的β-桶，含有8个跨膜结构域和4个胞外环。从多种革兰氏阴性病原体中鉴定了同源物，包括汉氏巴尔通体Pap 31、布鲁氏菌Omp 31、根癌农杆菌Omp 25和奈瑟菌不透明蛋白（Opa）。家族成员在体外合成的蛋白质表达范围从约。26.5至35.1kDa，除了HbpB，HbpB是一种55.9kDa的蛋白质，其各自的基因已被含有可变数目串联重复的富含GC的元件破坏。通过定量逆转录酶-PCR（RT-PCR）的转录分析表明，所有家族成员在正常培养条件下表达，其中hbpD和hbpB转录本分别是最丰富和最罕见的。突变的hbpA等位基因交换产生的菌株，表现出增强的氯化血红素结合表型相对于亲本菌株，和定量RT-PCR分析显示升高的转录水平为其他hbpfamily成员，这表明发生补偿性表达。
Bartonella quintana, the agent of trench fever and an etiologic agent of bacillary angiomatosis, has an extraordinarily high hemin requirement for growth compared to other bacterial pathogens. We previously identified the major hemin receptor of the pathogen as a 30-kDa surface protein, termed HbpA. This report describes four additional homologues that share approximately 48% amino acid sequence identity withhbpA. Three of the genes form a paralagous cluster, termedhbpCAB, whereas the other members,hbpDandhbpE, are unlinked. Secondary structure predictions and other evidence suggest that Hbp family members are β-barrels located in the outer membrane and contain eight transmembrane domains plus four extracellular loops. Homologs from a variety of gram-negative pathogens were identified, includingBartonella henselaePap31,BrucellaOmp31,Agrobacterium tumefaciensOmp25, and neisserial opacity proteins (Opa). Family members expressed in vitro-synthesized proteins ranging from ca. 26.5 to 35.1 kDa, with the exception of HbpB, an ∼55.9-kDa protein whose respective gene has been disrupted by a ∼510 GC-rich element containing variable-number tandem repeats. Transcription analysis by quantitative reverse transcriptase-PCR (RT-PCR) indicates that all family members are expressed under normal culture conditions, withhbpDandhbpBtranscripts being the most abundant and the rarest, respectively. Mutagenesis ofhbpAby allelic exchange produced a strain that exhibited an enhanced hemin-binding phenotype relative to the parental strain, and analysis by quantitative RT-PCR showed elevated transcript levels for the otherhbpfamily members, suggesting that compensatory expression occurs.