PROTEIN FILAMENTS MAY INITIATE THE ASSEMBLY OF THE BACILLUS-SUBTILIS SPORE COAT
PROTEIN FILAMENTS MAY INITIATE THE ASSEMBLY OF THE BACILLUS-SUBTILIS SPORE COAT
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DOI：
10.1016/0300-9084(92)90138-5
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发表时间：
1992-07-01
期刊：
影响因子：
3.9
通讯作者：
FITZJAMES, PC
中科院分区：
文献类型：
--
作者：
ARONSON, AI;EKANAYAKE, L;FITZJAMES, PC
枯草芽孢杆菌孢子被由三层形态学结构组成：一层弥散的底被、一层条纹状的内被和一层染色密集的外被。这些层由至少15种多肽组成，特别是CotE的缺失具有广泛的多效性效应。只有一个部分的内涂层上存在的孢子是溶菌酶敏感的。这些孢子的初始萌发率与野生型相同，但由于萌发孢子的不完整孢子衣的损失，总体光密度降低明显更大。溶菌酶敏感表型的抑制剂有一些外壳蛋白恢复，以及一些新的次要多肽。这些孢子仍然缺乏一层内被，并像cotE缺失菌株产生的孢子一样萌发。CotE蛋白合成开始于孢子形成的阶段II-III，早在孢子上的外壳出现在阶段IV-V。尽管其明显的亲水性，这种蛋白质是存在于从孢子形成细胞的粗不溶性部分。CotE不被高或低离子强度缓冲液溶解，也不被用于溶解膜蛋白的洗涤剂溶解。需要8 M尿素或6 M盐酸胍，并且针对低离子强度缓冲液的透析导致聚集成长的粘性细丝。CotE和CotT孢子外壳蛋白似乎是必要的，这些丝的形成。这些蛋白质中的每一个都含有与牛中间丝蛋白相关的序列，因此它们的相互作用可能导致类似的结构。这些细丝的性质与它们作为孢子底被层的初始组分沉积在外前孢子膜上是一致的。
The Bacillus subtilis spore coat consists of three morphological layers: a diffuse undercoat, a striated inner coat and a densely staining outer coat. These layers are comprised of at least 15 polypeptides and the absence of one in particular, CotE, had extensive pleiotropic effects. Only a partial inner coat was present on the spores which were lysozyme-sensitive. The initial rate of germination of these spores was the same as for the wild type but the overall optical density decrease was greater apparently due to the loss of the incomplete spore coat from germinated spores. Suppressors of the lysozyme-sensitive phenotype had some outer coat proteins restored as well as some novel minor polypeptides. These spores still lacked an undercoat and germinated as did those produced by the cotE deletion strain. The CotE protein was synthesized starting at stage II-III of sporulation, long before the appearance of the coat on spores at stage IV-V. Despite its apparent hydrophilic properties, this protein was present in the crude insoluble fraction from sporulating cells. CotE was not solubilized by high or low ionic strength buffers nor by detergents used for the solubilization of membrane proteins. Either 8 M urea or 6 M guanidine HCl was required and dialysis against a low ionic strength buffer resulted in aggregation into long, sticky filaments. Both the CotE and CotT spore coat proteins appeared to be necessary for the formation of these filaments. Each of these proteins contains sequences related to a bovine intermediate filament protein so their interaction could result in an analogous structure. The properties of these filaments are consistent with their deposition on the outer forespore membrane as the initial components of the spore undercoat layer.