Multiple functions of the leucine-rich repeat protein LrrA of Treponema denticola
Multiple functions of the leucine-rich repeat protein LrrA of Treponema denticola
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DOI：
10.1128/iai.72.8.4619-4627.2004
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发表时间：
2004-08-01
影响因子：
3.1
通讯作者：
Kuramitsu, HK
中科院分区：
文献类型：
--
作者：
Ikegami, A;Honma, K;Kuramitsu, HK
已在齿垢密螺旋体ATCC 35405中鉴定了编码富含亮氨酸的重复蛋白LrrA的基因lrrA，所述LrrA含有23个氨基酸残基的8个共有串联重复。富含亮氨酸的重复序列通常是有用的蛋白质结合基序，并且含有该重复序列的蛋白质通常参与蛋白质-蛋白质相互作用。Southern杂交分析表明，T. denticola ATCC 35405表达lrrA基因，但在T.牙菌ATCC 33520。为了分析LrrA在T.构建了齿垢菌、菌株ATCC 35405的lrrA失活突变体和菌株ATCC 33520的lrrA基因表达转化体。对突变体和突变体的鉴定表明，LrrA与T.并表现出多功能特性。结果表明，菌株ATCC 35405与HEp-2细胞培养物的附着以及与Tannerella lasthensis的共聚集通过lrrA突变而减弱。此外，在体外结合试验表明，LrrA的特异性结合的一部分，坦纳氏菌富含亮氨酸的重复蛋白，BspA，这是介导的N-末端区域的LrrA。还观察到lrrA突变导致T. Denticola ATCC 35405，并因此减弱组织渗透。这些结果表明，富含亮氨酸的重复蛋白LrrA在人类上皮细胞的附着和渗透以及与Tannerella lasthensis的共聚集中起作用。这些特性可能对T.齿垢
The gene lrrA, encoding a leucine-rich repeat protein, LrrA, that contains eight consensus tandem repeats of 23 amino acid residues, has been identified in Treponema denticola ATCC 35405. A leucine-rich repeat is a generally useful protein-binding motif, and proteins containing this repeat are typically involved in protein-protein interactions. Southern blot analysis demonstrated that T. denticola ATCC 35405 expresses the lrrA gene, but the gene was not identified in T. denticola ATCC 33520. In order to analyze the functions of LrrA in T. denticola, an lrrA-inactivated mutant of strain ATCC 35405 and an lrrA gene expression transformant of strain ATCC 33520 were constructed. Characterization of the mutant and transformant demonstrated that LrrA is associated with the extracytoplasmic fraction of T. denticola and expresses multifunctional properties. It was demonstrated that the attachment of strain ATCC 35405 to HEp-2 cell cultures and coaggregation with Tannerella forsythensis were attenuated by the lrrA mutation. In addition, an in vitro binding assay demonstrated specific binding of LrrA to a portion of the Tannerella forsythensis leucine-rich repeat protein, BspA, which is mediated by the N-terminal region of LrrA. It was also observed that the lrrA mutation caused a reduction of swarming in T. denticola ATCC 35405 and consequently attenuated tissue penetration. These results suggest that the leucine-rich repeat protein LrrA plays a role in the attachment and penetration of human epithelial cells and coaggregation with Tannerella forsythensis. These properties may play important roles in the virulence of T. denticola.