Institute of Cytology, RAS, St Petersburg, Russia.
Institute of Molecular Genetics, RAS, Moscow, Russia.
FEBS Lett. 2020 Oct;594(19):3095-3107. doi: 10.1002/1873-3468.13897. Epub 2020 Aug 14.
Protealysin is a thermolysin-like protease of Serratia proteamaculans capable of specifically cleaving actin, which correlates with the invasive activity of these bacteria. Here, we show that inactivation of the protealysin gene does not inhibit invasion but, in contrast, leads to a twofold increase in the S. proteamaculans invasive activity. By mass spectrometry, we identified the outer membrane protein OmpX as a substrate of protealysin. Recombinant E. coli carrying the OmpX gene truncated by 40 N-terminal residues or both the OmpX and protealysin genes, in contrast to the full-length OmpX, do not increase adhesion of these bacteria, indicating that the 40 N-terminal residues of OmpX are indispensable for S. proteamaculans invasion. Our results show that both protealysin and its substrates can stimulate Serratia invasion.
蛋白酶是一种来自变形菌属的亮氨酸蛋白酶，能够特异性地切割肌动蛋白，这与这些细菌的侵袭活性相关。在这里，我们表明蛋白酶基因的失活并不会抑制侵袭，反而会使变形菌属的侵袭活性增加两倍。通过质谱分析，我们鉴定出外膜蛋白 OmpX 是蛋白酶的底物。与全长 OmpX 相比，携带 OmpX 基因缺失 40 个 N 端残基或同时缺失 OmpX 和蛋白酶基因的重组大肠杆菌不会增加这些细菌的黏附，表明 OmpX 的 40 个 N 端残基对变形菌属的侵袭是必不可少的。我们的结果表明，蛋白酶及其底物都可以刺激变形菌属的侵袭。
