Domain Analysis of Protein P30 in Mycoplasma pneumoniae Cytadherence and Gliding Motility
Domain Analysis of Protein P30 in Mycoplasma pneumoniae Cytadherence and Gliding Motility
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DOI：
10.1128/jb.01228-10
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发表时间：
2011-04-01
影响因子：
3.2
通讯作者：
Krause, Duncan C.
中科院分区：
文献类型：
--
作者：
Chang, How-Yi;Jordan, Jarrat L.;Krause, Duncan C.
无细胞壁的原核生物肺炎支原体导致人类支气管炎和非典型肺炎。支原体附着和滑行运动是呼吸道上皮定植所必需的，主要由分化的终末细胞器介导。P30是一种位于细胞器末端的膜蛋白，是细胞粘附和滑动运动所必需的，但对其特异性结构域的功能作用知之甚少。在目前的研究中，P30的结构域缺失和取代衍生物被工程化并通过转座子递送引入P30无效突变体中以评估它们拯救P30功能的能力。涉及P30胞外区的结构域缺失严重影响蛋白质稳定性和粘附和滑动功能，以及稳定末端细胞器蛋白P65的能力。跨膜结构域中的氨基酸取代揭示了P30稳定性和功能所独特需要的特定残基，这可能是为了在膜中建立正确的拓扑结构以与结合伴侣进行有效对齐。预测的胞质结构域内的缺失不影响P30的定位或其能力，以稳定P65，但明显受损的滑动运动和细胞粘附。两个胞质结构域缺失中较大的一个似乎也去除了P30信号肽加工位点，表明前导肽比预期的大。我们建议，P30的胞质结构域可能需要连接P30的终端细胞器的核心，使P30的胞外结构域实现功能构象，或者两者兼而有之。
The cell wall-less prokaryote Mycoplasma pneumoniae causes bronchitis and atypical pneumonia in humans. Mycoplasma attachment and gliding motility are required for colonization of the respiratory epithelium and are mediated largely by a differentiated terminal organelle. P30 is a membrane protein at the distal end of the terminal organelle and is required for cytadherence and gliding motility, but little is known about the functional role of its specific domains. In the current study, domain deletion and substitution derivatives of P30 were engineered and introduced into a P30 null mutant by transposon delivery to assess their ability to rescue P30 function. Domain deletions involving the extracellular region of P30 severely impacted protein stability and adherence and gliding function, as well as the capacity to stabilize terminal organelle protein P65. Amino acid substitutions in the transmembrane domain revealed specific residues uniquely required for P30 stability and function, perhaps to establish correct topography in the membrane for effective alignment with binding partners. Deletions within the predicted cytoplasmic domain did not affect P30 localization or its capacity to stabilize P65 but markedly impaired gliding motility and cytadherence. The larger of two cytoplasmic domain deletions also appeared to remove the P30 signal peptide processing site, suggesting a larger leader peptide than expected. We propose that the P30 cytoplasmic domain may be required to link P30 to the terminal organelle core, to enable the P30 extracellular domain to achieve a functional conformation, or perhaps both.