Kim D W, Lin S J, Morita S, Terada I, Matsuzawa H
Department of Biotechnology, University of Tokyo, Japan.
Biochem Biophys Res Commun. 1997 Feb 24;231(3):535-9. doi: 10.1006/bbrc.1996.5899.
The precursor of aqualysin I, a subtilisin-type protease secreted by Thermus aquaticus, consists of four domains, an N-terminal signal sequence, an N-terminal pro-sequence, a protease domain, and a C-terminal pro-sequence. A non-covalent N-terminal pro-sequence facilitates the production of active aqualsin I, when the C-terminal pro-sequence is deleted. The role of the C-terminal pro-sequence in protein secretion was analyzed using a Saccharomyces cerevisiae expression system. Deletion of the C-terminal pro-sequence resulted in increased secretion of aqualysin I, i.e., about three times as much as that in the case of the wild type. In the case of the wild-type precursor, non-secreted aqualysin I with the C-terminal pro-sequence was retained in the endoplasmic reticulum in an inactive form, suggesting that the C-terminal pro-sequence prevents the protease domain from taking on a properly folded structure, unlike the N-terminal pro-sequence.
嗜热水生栖热菌分泌的枯草杆菌蛋白酶型蛋白酶嗜热栖热菌溶素I的前体由四个结构域组成，即一个N端信号序列、一个N端前序列、一个蛋白酶结构域和一个C端前序列。当C端前序列缺失时，非共价的N端前序列有助于活性嗜热栖热菌溶素I的产生。使用酿酒酵母表达系统分析了C端前序列在蛋白质分泌中的作用。C端前序列缺失导致嗜热栖热菌溶素I的分泌增加，即约为野生型情况下的三倍。在野生型前体的情况下，带有C端前序列的未分泌嗜热栖热菌溶素I以无活性形式保留在内质网中，这表明与N端前序列不同，C端前序列阻止蛋白酶结构域形成正确折叠的结构。
