Discovery and characterization of a novel family of prokaryotic nanocompartments involved in sulfur metabolism.
Discovery and characterization of a novel family of prokaryotic nanocompartments involved in sulfur metabolism.
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DOI：
10.7554/elife.59288
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发表时间：
2021-04-06
期刊：
影响因子：
7.7
通讯作者：
Savage DF
中科院分区：
文献类型：
--
作者：
Nichols RJ;LaFrance B;Phillips NR;Radford DR;Oltrogge LM;Valentin-Alvarado LE;Bischoff AJ;Nogales E;Savage DF
原核纳米隔室，也被称为包裹体，是最近在原核生物中发现的一种蛋白质类细胞器样隔室，用于分隔货物酶。虽然最初的研究已经开始阐明包封蛋白的结构和生理作用，但生物信息学证据表明，纳米室中包封蛋白的多样性仍未被探索。在这里，我们描述了淡水蓝藻长聚球菌PCC 7942中的一种新型胶囊。这种纳米室在硫酸盐饥饿时被上调，并通过n端靶向序列包封半胱氨酸脱硫酶。利用低温电子显微镜，我们确定了纳米室复合物的结构，分辨率为2.2 Å。最后，该配合物的生化表征表明，半胱氨酸脱硫酶的活性在包封后得到增强。总之，我们的发现、结构分析和这种原核纳米室的酶学表征为未来的研究提供了基础，旨在了解这种包封蛋白在各种细菌中的生理作用。
Prokaryotic nanocompartments, also known as encapsulins, are a recently discovered proteinaceous organelle-like compartment in prokaryotes that compartmentalize cargo enzymes. While initial studies have begun to elucidate the structure and physiological roles of encapsulins, bioinformatic evidence suggests that a great diversity of encapsulin nanocompartments remains unexplored. Here, we describe a novel encapsulin in the freshwater cyanobacterium Synechococcus elongatus PCC 7942. This nanocompartment is upregulated upon sulfate starvation and encapsulates a cysteine desulfurase enzyme via an N-terminal targeting sequence. Using cryo-electron microscopy, we have determined the structure of the nanocompartment complex to 2.2 Å resolution. Lastly, biochemical characterization of the complex demonstrated that the activity of the cysteine desulfurase is enhanced upon encapsulation. Taken together, our discovery, structural analysis, and enzymatic characterization of this prokaryotic nanocompartment provide a foundation for future studies seeking to understand the physiological role of this encapsulin in various bacteria.