Control of cell wall assembly by a histone-like protein in mycobacteria
Control of cell wall assembly by a histone-like protein in mycobacteria
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DOI：
10.1128/jb.00550-07
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发表时间：
2007-11-01
影响因子：
3.2
通讯作者：
Kobayashi, Kazuo
中科院分区：
文献类型：
--
作者：
Katsube, Tomoya;Matsumoto, Sohkichi;Kobayashi, Kazuo
细菌根据生长状态协调细胞壁的组装以及细胞组分的合成。分枝杆菌细胞壁主要由与糖（如海藻糖和阿拉伯糖）共价连接的分枝菌酸组成，并且对分枝杆菌的发病至关重要。分枝菌酸向糖的转移是细胞壁生物发生所必需的，并且由分枝菌酰转移酶介导，分枝菌酰转移酶先前已被鉴定为三种抗原85（Ag 85）复合物蛋白。然而，连接细胞壁生物发生和生长状态的调节机制尚未阐明。在这里，我们发现，组蛋白样蛋白具有双重浓度依赖性的调节作用，通过直接结合到Ag 85复合物和底物，海藻糖-6-monomycolate，在细胞壁中的Ag 85复合物的分枝菌酰转移酶功能。组蛋白样蛋白缺陷型耻垢分枝杆菌菌株具有不寻常的锯齿状细胞壁结构，并在生长迟缓期表现出糖脂生物合成的受损停止。此外，我们发现，人工改变细胞外组蛋白样蛋白和Ag 85复合物的量改变分枝杆菌的生长速率，这可能是由于糖脂生物合成的下调受损。我们的研究结果表明，新的调控细胞壁组装，这对细菌生长的影响。
Bacteria coordinate assembly of the cell wall as well as synthesis of cellular components depending on the growth state. The mycobacterial cell wall is dominated by mycolic acids covalently linked to sugars, such as trehalose and arabinose, and is critical for pathogenesis of mycobacteria. Transfer of mycolic acids to sugars is necessary for cell wall biogenesis and is mediated by mycolyltransferases, which have been previously identified as three antigen 85 (Ag85) complex proteins. However, the regulation mechanism which links cell wall biogenesis and the growth state has not been elucidated. Here we found that a histone-like protein has a dual concentration-dependent regulatory effect on mycolyltransferase functions of the Ag85 complex through direct binding to both the Ag85 complex and the substrate, trehalose-6-monomycolate, in the cell wall. A histone-like protein-deficient Mycobacterium smegmatis strain has an unusual crenellated cell wall structure and exhibits impaired cessation of glycolipid biosynthesis in the growth-retarded phase. Furthermore, we found that artificial alteration of the amount of the extracellular histone-like protein and the Ag85 complex changes the growth rate of mycobacteria, perhaps due to impaired down-regulation of glycolipid biosynthesis. Our results demonstrate novel regulation of cell wall assembly which has an impact on bacterial growth.