Sequence of the lktB gene from Actinobacillus actinomycetemcomitans.
Sequence of the lktB gene from Actinobacillus actinomycetemcomitans.
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来自伴放线放线杆菌的 lktB 基因序列。
DOI：
10.1093/nar/18.17.5291
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发表时间：
1990
影响因子：
14.9
通讯作者：
Kraig,E
中科院分区：
文献类型：
--
作者：
Guthmiller,JM;Kolodrubetz,D;Cagle,MP;Kraig,E
我们先前报道了伴放线放线杆菌（Actinobacillus actino-mycetemcomitans）白细胞毒素基因lktA的克隆、测序和表达，伴放线杆菌是一种革兰氏阴性细菌，与局部青少年牙周炎的病因有关。该基因编码的蛋白质与来自其他潜在致病性细菌的毒素具有超过42%的同一性，包括来自溶血性巴氏杆菌3的白细胞毒素（Lkt）和来自大肠杆菌的α-溶血素（Hly）。大肠杆菌4.在这些细菌中，毒素的结构基因紧邻lktB/hlyB基因的上游，lktB/hlyB基因编码毒素分泌所必需的蛋白质5。A.据报道，伴放线菌存在于周质中，而不是分泌6。因此，我们对先前克隆的A中lktA下游区域进行了测序。结果表明，该基因编码一个功能性LktB蛋白。使用对lktB开放阅读框特异的杂交探针进行的北方印迹分析表明该基因被转录（Spitznagel，Kraig和Kolodrubetz，准备中）。根据推导的氨基酸序列，LktB蛋白与溶血性巴斯德菌7的相应蛋白同源，同源性为81%，与大肠杆菌的HlyB蛋白同源。coli 4，同源性为83%。76%的残基在所有三种蛋白质中是相同的。这种高度的相似性与转运中的共同功能一致，并表明应重新研究白细胞毒素的可能分泌。
We previously reported the cloning, sequencing and expression of the leukotoxin gene, lktA, from Actinobacillus actino-mycetemcomitans, a gram negative bacterium which has been implicated in the etiology of localized juvenile periodontitis" 2. This gene encodes a protein that is over 42% identical to toxins from other potentially pathogenic bacteria, including the leukotoxin (Lkt) from Pasteurella haemolytica3 and the a-hemolysin (Hly) from E. coli4. In each of these bacteria, the structural gene for the toxin is immediately upstream of a gene, lktB/hlyB, that encodes a protein essential for the secretion of the toxin5. The leukotoxin from A. actinomycetemcomitans is reportedly found in the periplasm rather than being secreted6. Therefore, we have sequenced the previously cloned region downstream of lktA in A. actinomycetemcomitans and demonstrate that it could encode a functional LktB protein. Northern blot analysis using hybridization probes specific for the open reading frame of lktB indicate that this gene is transcribed (Spitznagel, Kraig, and Kolodrubetz, in preparation). Based on the deduced amino acid sequence, the LktB protein is homologous to the corresponding protein of P. haemolytica7, 81% identity, and to the HlyB protein of E. coli4, 83% identity. 76% of the residues are identical in all three proteins. This high degree of similarity is consistent with a common function in transport and suggests that the possible secretion of the leukotoxin should be re-investigated.