Interest in protein disulfide bond formation has recently increased because of the prominent role of disulfide bonds in bacterial virulence and survival. The first discovered pathway that introduces disulfide bonds into cell envelope proteins consists of Escherichia coli enzymes DsbA and DsbB. Since its discovery, variations on the DsbAB pathway have been found in bacteria and archaea, probably reflecting specific requirements for survival in their ecological niches. One variation found amongst Actinobacteria and Cyanobacteria is the replacement of DsbB by a homologue of human vitamin K epoxide reductase. Many Gram-positive bacteria express enzymes involved in disulfide bond formation that are similar, but non-homologous, to DsbAB. While bacterial pathways promote disulfide bond formation in the bacterial cell envelope, some archaeal extremophiles express proteins with disulfide bonds both in the cytoplasm and in the extra-cytoplasmic space, possibly to stabilize proteins in the face of extreme conditions, such as growth at high temperatures. Here, we summarize the diversity of disulfide-bond-catalysing systems across prokaryotic lineages, discuss examples for understanding the biological basis of such systems, and present perspectives on how such systems are enabling advances in biomedical engineering and drug development.

中文翻译：

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原核生物中二硫键的形成。

由于二硫键在细菌毒力和存活中的突出作用，最近对蛋白质二硫键形成的兴趣增加了。第一个发现的将二硫键引入细胞包膜蛋白的途径由大肠杆菌酶 DsbA 和 DsbB 组成。自发现以来，在细菌和古细菌中发现了 DsbAB 途径的变异，这可能反映了在其生态位中生存的特定要求。在放线菌和蓝细菌中发现的一种变异是用人类维生素 K 环氧化物还原酶的同源物替代 DsbB。许多革兰氏阳性细菌表达与 DsbAB 相似但非同源的二硫键形成酶。虽然细菌途径促进细菌细胞包膜中二硫键的形成，一些古细菌嗜极菌在细胞质和细胞质外空间中表达具有二硫键的蛋白质，可能是为了在极端条件下稳定蛋白质，例如在高温下生长。在这里，我们总结了原核生物谱系中二硫键催化系统的多样性，讨论了理解此类系统生物学基础的示例，并就此类系统如何推动生物医学工程和药物开发的进展提出了看法。