Mutation of the Conserved Calcium-Binding Motif in Neisseria gonorrhoeae PilC1 Impacts Adhesion but Not Piliation
Mutation of the Conserved Calcium-Binding Motif in Neisseria gonorrhoeae PilC1 Impacts Adhesion but Not Piliation
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DOI：
10.1128/iai.00493-13
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发表时间：
2013-11-01
影响因子：
3.1
通讯作者：
Thomas, Christopher E.
中科院分区：
文献类型：
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作者：
Cheng, Yuan;Johnson, Michael D. L.;Thomas, Christopher E.
淋病奈瑟菌PilC 1是在奈瑟菌属和其他产生IV型菌毛的属中发现的IV型菌毛相关粘附素的PilC家族的成员。以前，在铜绿假单胞菌的PilY 1的C-末端结构域和Kingella kingae的PilC 1和PilC 2中描述了钙结合结构域。遗传分析表明，N.淋病的PilC 1中揭示了类似的钙结合基序。为了评价N.淋病，我们生产的重组全长PilC 1和PilC 1的C-末端结构域片段。我们发现，虽然钙结合基序的改变破坏了PilC 1结合钙的能力，但它们并没有严重影响蛋白质的二级结构。此外，我们证明，全长野生型PilC 1和全长钙结合缺陷PilC 1抑制淋球菌粘附培养的人宫颈上皮细胞，不像截短PilC 1的C-末端结构域。与K中的PilC 1相似。kingae，但与铜绿假单胞菌PilY 1的钙结合突变体相反，N.淋病PilC 1产生正常量的皮利。然而，N.淋病奈瑟菌PilC 1钙结合突变体在淋球菌对ME 180细胞的粘附和遗传转化方面仍存在部分缺陷，这两个方面都是该人类病原体的重要毒力因子。因此，我们得出结论，钙结合PilC 1在菌毛功能中起着关键作用。淋病
Neisseria gonorrhoeae PilC1 is a member of the PilC family of type IV pilus-associated adhesins found in Neisseria species and other type IV pilus-producing genera. Previously, a calcium-binding domain was described in the C-terminal domains of PilY1 of Pseudomonas aeruginosa and in PilC1 and PilC2 of Kingella kingae. Genetic analysis of N. gonorrhoeae revealed a similar calcium-binding motif in PilC1. To evaluate the potential significance of this calcium-binding region in N. gonorrhoeae, we produced recombinant full-length PilC1 and a PilC1 C-terminal domain fragment. We show that, while alterations of the calcium-binding motif disrupted the ability of PilC1 to bind calcium, they did not grossly affect the secondary structure of the protein. Furthermore, we demonstrate that both full-length wild-type PilC1 and full-length calcium-binding-deficient PilC1 inhibited gonococcal adherence to cultured human cervical epithelial cells, unlike the truncated PilC1 C-terminal domain. Similar to PilC1 in K. kingae, but in contrast to the calcium-binding mutant of P. aeruginosa PilY1, an equivalent mutation in N. gonorrhoeae PilC1 produced normal amounts of pili. However, the N. gonorrhoeae PilC1 calcium-binding mutant still had partial defects in gonococcal adhesion to ME180 cells and genetic transformation, which are both essential virulence factors in this human pathogen. Thus, we conclude that calcium binding to PilC1 plays a critical role in pilus function in N. gonorrhoeae.