Jacobs M, Andersen J B, Kontinen V, Sarvas M
Department of Microbiology, Technical University of Denmark, Lyngby.
Mol Microbiol. 1993 May;8(5):957-66. doi: 10.1111/j.1365-2958.1993.tb01640.x.
In prsA (protein secretion) mutants of Bacillus subtilis, decreased levels of exoproteins, including alpha-amylase and subtilisins, are found extracellularly. The effect of prsA on subtilisin secretion is elaborated here. Extracytoplasmic folding and secretion of active subtilisin is assisted by the N-terminal pro-sequence of its precursor. In this paper we present evidence that the product of the prsA gene is additionally required for these processes in vivo. We examined inducible expression of different subtilisin-alkaline phosphatase fusion genes in the prsA3 mutant. We found massive degradation of the fusion proteins, and a lack of enzymatic activity in the protein secreted. We suggest that PrsA is a novel chaperone with a predicted extracytoplasmic location, and is important in vivo for the proper conformation of various exoproteins, including those with pro-sequence (like subtilisin) and those without (like alpha-amylase).
在枯草芽孢杆菌的prsA（蛋白质分泌）突变体中，胞外发现包括α-淀粉酶和枯草杆菌蛋白酶在内的胞外蛋白水平降低。本文阐述了prsA对枯草杆菌蛋白酶分泌的影响。活性枯草杆菌蛋白酶的胞质外折叠和分泌由其前体的N端前序列辅助。在本文中，我们提供证据表明，prsA基因的产物在体内这些过程中也是必需的。我们检测了prsA3突变体中不同枯草杆菌蛋白酶-碱性磷酸酶融合基因的诱导表达。我们发现融合蛋白大量降解，且分泌的蛋白质缺乏酶活性。我们认为PrsA是一种预测位于胞外的新型伴侣蛋白，在体内对包括有前序列的蛋白（如枯草杆菌蛋白酶）和无前序列的蛋白（如α-淀粉酶）等各种胞外蛋白的正确构象很重要。
