Pilin-like proteins in the extremely thermophilic bacterium Thermus thermophilus HB27:: Implication in competence for natural transformation and links to type IV pilus biogenesis
Pilin-like proteins in the extremely thermophilic bacterium Thermus thermophilus HB27:: Implication in competence for natural transformation and links to type IV pilus biogenesis
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DOI：
10.1128/aem.69.7.3695-3700.2003
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发表时间：
2003-07-01
影响因子：
4.4
通讯作者：
Averhoff, B
中科院分区：
文献类型：
--
作者：
Friedrich, A;Rumszauer, J;Averhoff, B
极端嗜热栖热菌 HB27 表现出高频率的自然转化。尽管我们最近报道了栖热菌中第一个能力基因的鉴定，但 DNA 摄取的分子基础尚不清楚。假定涉及菌毛状结构。在嗜热链球菌基因组的三个基因座中鉴定出编码前菌毛蛋白样蛋白的 12 个基因。本文描述的突变分析表明，一个基因座包含四个编码前毛蛋白样蛋白（pilA1 至 piLA4）的基因，对于自然转化至关重要。此外，还鉴定出了与已知基因没有相似性的新能力基因 comZ。对绒毛表型的分析揭示了 pilA1-pilA3Deltakat 突变体和 comZ 突变体的野生型绒毛作用，而 piLA4 突变体被发现完全没有菌毛结构。这些发现，加上 PilA4 与前菌毛素的显着相似性，得出这样的结论：嗜热丝虫菌毛结构是 IV 型菌毛。此外，pilA4 突变体中转化和纤毛表型的丧失表明 IV 型菌毛与嗜热链球菌 HB27 的自然转化有关。
The extreme thermophile Thermus thermophilus HB27 exhibits high frequencies of natural transformation. Although we recently reported identification of the first competence genes in Thermus, the molecular basis of DNA uptake is unknown. A pilus-like structure is assumed to be involved. Twelve genes encoding prepilin-like proteins were identified in three loci in the genome of T. thermophilus. Mutational analyses, described in this paper, revealed that one locus, which contains four genes that encode prepilin-like proteins (pilA1 to piLA4), is essential for natural transformation. Additionally, comZ, a new competence gene with no similarity to known genes, was identified. Analysis of the piliation phenotype revealed wild-type piliation of a pilA1-pilA3Deltakat mutant and a comZ mutant, whereas a piLA4 mutant was found to be completely devoid of pilus structures. These findings, together with the significant similarity of PilA4 to prepilins, led to the conclusion that the T. thermophilus pilus structures are type IV pili. Furthermore, the loss of the transformation and piliation phenotype in the pilA4 mutant suggests that type IV pili are implicated in natural transformation of T. thermophilus HB27.