Modular Arrangement of Allelic Variants Explains the Divergence in Moraxella catarrhalis UspA Protein Function
Modular Arrangement of Allelic Variants Explains the Divergence in Moraxella catarrhalis UspA Protein Function
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DOI：
10.1128/iai.00573-08
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发表时间：
2008-11-01
影响因子：
3.1
通讯作者：
Gray-Owen, Scott D.
中科院分区：
文献类型：
--
作者：
Brooks, Michael J.;Sedillo, Jennifer L.;Gray-Owen, Scott D.
卡他莫拉菌的泛在表面蛋白A分子（UspAs）是大的、非菌毛的、自转运蛋白，其可通过透射电子显微镜观察为细菌表面的“模糊”层。先前的研究将广泛的功能和结合活性归因于密切相关的UspA 1、UspA 2和/或UspA 2 H蛋白，然而这些活性之间的分子和系统发育关系在很大程度上仍未被探索。为了解决这个问题，我们确定了来自各种独立的M.卡他分离物，并将推导的氨基酸序列与先前表征的UspA 1、UspA 2和UspA 2 H蛋白的氨基酸序列进行比较。而不是保守的蛋白质，我们观察到一个显着的分歧，个别UspA 1，UspA 2，和UspA 2 H蛋白产生的模块化分类无关的肽序列的“盒”。某些变体盒的交换与UspA蛋白功能的菌株特异性差异相关，并赋予这些粘膜表面病原体不同的表型。
Ubiquitous surface protein A molecules (UspAs) of Moraxella catarrhalis are large, nonfimbrial, autotransporter proteins that can be visualized as a "fuzzy" layer on the bacterial surface by transmission electron microscopy. Previous studies attributed a wide array of functions and binding activities to the closely related UspA1, UspA2, and/or UspA2H protein, yet the molecular and phylogenetic relationships among these activities remain largely unexplored. To address this issue, we determined the nucleotide sequence of the uspA1 genes from a variety of independent M. catarrhalis isolates and compared the deduced amino acid sequences to those of the previously characterized UspA1, UspA2, and UspA2H proteins. Rather than being conserved proteins, we observed a striking divergence of individual UspA1, UspA2, and UspA2H proteins resulting from the modular assortment of unrelated "cassettes" of peptide sequence. The exchange of certain variant cassettes correlates with strain-specific differences in UspA protein function and confers differing phenotypes upon these mucosal surface pathogens.