The conserved carboxyl domain of MorC, an inner membrane protein of Aggregatibacter actinomycetemcomitans, is essential for membrane function.
The conserved carboxyl domain of MorC, an inner membrane protein of Aggregatibacter actinomycetemcomitans, is essential for membrane function.
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DOI：
10.1111/omi.12120
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发表时间：
2016-02
影响因子：
3.7
通讯作者：
Mintz KP
中科院分区：
文献类型：
--
作者：
Smith KP;Voogt RD;Ruiz T;Mintz KP
伴放线聚集杆菌的形态发生蛋白C（Morphogenesis protein C，MorC）对维持该口腔病原菌的细胞膜形态和完整性具有重要作用。MorC序列和操纵子组织被发现是保守的γ-变形菌，基于生物信息学分析的435个序列的代表性生物。利用A.用伴放线菌morC突变体作为模型系统来表达来自γ-变形菌门的四种遗传多样性代表的MorC同系物：流感嗜血杆菌、大肠杆菌、铜绿假单胞菌和卡他莫拉菌。助理评估表达同源蛋白的伴放线菌菌株对胆汁盐的敏感性、白细胞毒素分泌、自聚集和膜形态。MorC来自最密切相关的生物体（H. influenzae）与A.伴放线菌然而，来自亲缘关系较远的生物体的基因恢复了部分但不是全部的A。伴放线菌突变体表型。此外，缺失突变表明，蛋白质的最保守的部分，羧基末端DUF 490结构域，是必要的，以保持膜的完整性。缺失A.伴随放线菌MorC蛋白足以破坏膜稳定性和白细胞毒素分泌。这些数据表明，MorC序列在γ-变形菌中是功能保守的，并且该蛋白的羧基末端对于维持膜生理学是必不可少的。
Morphogenesis protein C (MorC) of Aggregatibacter actinomycetemcomitans is important for maintaining the membrane morphology and integrity of the cell envelope of this oral pathogen. The MorC sequence and operon organization was found to be conserved in Gammaproteobacteria, based on a bioinformatic analysis of 435 sequences from representative organisms. Functional conservation of MorC was investigated utilizing an A. actinomycetemcomitans morC mutant as a model system to express MorC homologs from four phylogenetically diverse representatives of the Gammaproteobacteria: Haemophilus influenzae; Escherichia coli; Pseudomonas aeruginosa; and Moraxella catarrhalis. The A. actinomycetemcomitans strains expressing the homologous proteins were assessed for sensitivity to bile salts, leukotoxin secretion, autoaggregation and membrane morphology. MorC from the most closely related organism (H. influenzae) was functionally identical to MorC from A. actinomycetemcomitans. However, the genes from more distantly related organisms restored some but not all A. actinomycetemcomitans mutant phenotypes. In addition, deletion mutagenesis indicated that the most conserved portion of the protein, the carboxyl terminus DUF490 domain, was necessary to maintain the integrity of the membrane. Deletion of the last ten amino acids of this domain of the A. actinomycetemcomitans MorC protein was sufficient to disrupt membrane stability and leukotoxin secretion. The data suggest that the MorC sequence is functionally conserved across Gammaproteobacteria and the carboxyl terminus of the protein is essential for maintaining membrane physiology.