Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA.
Appl Environ Microbiol. 2013 Nov;79(21):6637-46. doi: 10.1128/AEM.01627-13. Epub 2013 Aug 23.
The genome of the hyperthermophilic bacterium Thermotoga maritima encodes numerous putative peptides/proteins of 100 amino acids or less. While most of these open reading frames (ORFs) are transcribed during growth, their corresponding physiological roles are largely unknown. The onset of stationary phase in T. maritima was accompanied by significant morphological changes and upregulation of several ORFs located in the TM1298-TM1336 genome locus. This region contains putative HicAB toxin-antitoxin pairs, hypothetical proteins, radical S-adenosylmethionine (SAM) enzymes, and ABC transporters. Of particular note was the TM1315-TM1319 operon, which includes a putative 31-amino-acid peptide (TM1316) that was the most highly transcribed gene in the transcriptome during stationary phase. Antibodies directed against a synthetic version of TM1316 were used to track its production, which correlated closely with transcriptomic data. Immunofluorescence microscopy revealed that TM1316 was localized to the cell envelope and prominent in cell aggregates formed during stationary phase. The only functionally characterized locus with an organization similar to that of TM1315-TM1319 is in Bacillus subtilis, which contains subtilosin A, a cyclic peptide with Cys-to-α-carbon linkages that functions as an antilisterial bacteriocin. While the organization of TM1316 resembled that of the Bacillus peptide (e.g., in its number of amino acids and spacing of Cys residues), preparations containing high levels of TM1316 affected the growth of neither Thermotoga species nor Pyrococcus furiosus, a hyperthermophilic archaeon isolated from the same locale as T. maritima. Several other putative Cys-rich peptides could be identified in the TM1298-TM1336 locus, and while their roles are also unclear, they merit examination as potential antimicrobial agents in hyperthermophilic biotopes.
嗜热古菌 Thermotoga maritima 的基因组编码了许多推测的 100 个氨基酸或更少的肽/蛋白。虽然这些开放阅读框 (ORFs) 在生长过程中大部分都被转录，但它们对应的生理功能在很大程度上是未知的。Thermotoga maritima 进入静止期时，伴随着显著的形态变化和位于 TM1298-TM1336 基因组位置的多个 ORF 的上调。这个区域包含推测的 HicAB 毒素-抗毒素对、假设蛋白、激进的 S-腺苷甲硫氨酸 (SAM) 酶和 ABC 转运体。特别值得注意的是 TM1315-TM1319 操纵子，它包含一个推测的 31 个氨基酸的肽 (TM1316)，在静止期转录组中是转录水平最高的基因。针对 TM1316 的合成版本的抗体被用来追踪它的产生，这与转录组数据密切相关。免疫荧光显微镜显示，TM1316 定位于细胞包膜上，在静止期形成的细胞聚集体中很明显。唯一一个与 TM1315-TM1319 组织相似的功能特征的基因座是在枯草芽孢杆菌中，它含有枯草菌素 A，这是一种具有 Cys-to-α-碳键的环状肽，作为一种抗李斯特菌的细菌素。虽然 TM1316 的组织类似于芽孢杆菌肽（例如，在其氨基酸数量和 Cys 残基的间隔方面），但含有高水平 TM1316 的制剂既不影响 Thermotoga 物种的生长，也不影响 Pyrococcus furiosus 的生长，后者是从与 Thermotoga maritima 相同的地方分离出来的高温古菌。在 TM1298-TM1336 基因座中还可以识别出其他几种推测的富含 Cys 的肽，虽然它们的作用也不清楚，但值得作为高温生物区系中潜在的抗菌剂进行研究。
