SECRETION OF PERTUSSIS TOXIN FROM BORDETELLA PERTUSSIS

之前，我们证明了一组八个基因的存在， 是从B分泌百日咳毒素（PT）所必需的。 百日咳。 这些基因称为ptl基因，编码转运蛋白， 与参与运输的蛋白质家族具有同源性， DNA和蛋白质都能穿过细菌膜。 我们现在有证据 第九种分泌基因 这个小基因ptl 1被预测编码 一种6.8kDa的蛋白质，位于ptlD和ptlE之间。 PtlI股份 与VirB 7的同源性，这是T-DNA跨膜转运所必需的。 植物病原体根癌农杆菌的膜。 删除 来自B的ptlI区域。百日咳对PtlE没有明显的影响， 导致可检测的PtlF的丢失，表明PtlI可能相互作用 并稳定PtIF。 使用免疫沉淀技术，我们 证明了PtlI和PtlF之间的直接相互作用。 这些结果 是Ptl蛋白之间相互作用的第一个证据。 此外 为了阐明Ptl蛋白之间的相互作用，我们 还研究了Ptl蛋白促进 运输PT。 一种Ptl蛋白，特别是PtlC， 有趣的特征是它含有核苷酸结合基序。 我们目前正在纯化这种蛋白质， 蛋白质具有水解酶或激酶活性， 在运输过程中发挥重要作用。 这项工作增加了我们的 知识的分泌PT，并可能有助于建设 B.百日咳杆菌，其有效地产生和分泌PT。 等 菌株将可用于疫苗生产。 此外，知识 PT分泌机制的研究可能有助于 分泌灭活形式PT的减毒活疫苗，因此 引发保护性免疫反应

Previously, we demonstrated the existence of a set of eight genes that are essential for the secretion of pertussis toxin (PT) from B. pertussis. These genes, termed ptl genes, encode transport proteins that share homology with a family of proteins involved in the transport of both DNA and proteins across bacterial membranes. We now have evidence for a ninth secretion gene. This small gene, ptl1 is predicted to encode a protein of 6.8 kDa and is located between ptlD and ptlE. PtlI shares homology with VirB7 which is required for transport of T-DNA across the membranes of the plant pathogen Agrobacterium tumefaciens. Deletion of the ptlI region from B. pertussis has no discernable effect of PtlE but resulted in loss of detectable PtlF, suggesting the PtlI may interact with and stabilize PtlF. Using immunoprecipitation techniques, we demonstrated a direct interaction between PtlI and PtlF. These results are the first evidence of interactions between Ptl proteins. In addition to the work on elucidation of interactions between Ptl proteins, we are also investigating the mechanism by which the Ptl proteins promote transport of PT. One Ptl protein in particular, PtlC, has the interesting characteristic that it contains a nucleotide binding motif. We are currently purifying this protein and determining whether this protein has either hydrolase or kinase activity that might play a critical role in the transport process. This work increases our knowledge of the secretion of PT and may aid in the construction of strains of B. pertussis which efficiently produce and secrete PT. Such strains would be useful for vaccine production. In addition, knowledge of the mechanism of PT secretion might aid in the development of live-attenuated vaccines that secrete inactivated forms of PT, thus inducing a protective immune response.