Rhomboid proteases were discovered almost 15 years ago and are structurally the best characterized intramembrane proteases. Apart from the general serine protease inhibitor 3,4-dichloro-isocoumarin (DCI) and a few crystal structures of the Escherichia coli rhomboid GlpG with other inhibitors, there is surprisingly little information about inhibitors of rhomboids from other species, probably because of a lack of general methods to measure inhibition against different rhomboid species. We here present activity-based protein profiling (ABPP) as a general method to screen rhomboids for their activity and inhibition. Using ABPP, we compare the inhibitory capacity of 50 small molecules against 13 different rhomboids. We find one new pan rhomboid inhibitor and several inhibitors that display selectivity. We also demonstrate that inhibition profile and sequence similarity of rhomboids are not related, which suggests that related rhomboids may be selectively inhibited. Finally, by making use of the here discovered inhibitors, we were able to show that two bacterial rhomboids autoprocess themselves in their N-terminal part.

中文翻译：

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通过基于活动的蛋白质谱分析的菱形蛋白酶的抑制剂指纹图谱显示抑制剂选择性和菱形自动加工

菱形蛋白酶在将近15年前被发现，并且在结构上是特征最鲜明的膜内蛋白酶。除了普通的丝氨酸蛋白酶抑制剂3,4-二氯异香豆素（DCI）和大肠杆菌的一些晶体结构与其他抑制剂形成的菱形GlpG相比，令人惊讶的是，关于来自其他物种的菱形抑制剂的信息很少，这可能是由于缺乏测量针对不同菱形物种的抑制作用的通用方法所致。我们在这里介绍基于活性的蛋白质谱分析（ABPP），作为筛选菱形活性和抑制作用的常规方法。使用ABPP，我们比较了50种小分子对13种不同菱形的抑制能力。我们发现一种新的泛菱形抑制剂和几种具有选择性的抑制剂。我们还证明，菱形的抑制谱和序列相似性不相关，这表明相关的菱形可以被选择性地抑制。最后，通过使用此处发现的抑制剂，