Structural Basis for the Kexin-like Serine Protease from Aeromonas sobria as Sepsis-causing Factor
Structural Basis for the Kexin-like Serine Protease from Aeromonas sobria as Sepsis-causing Factor
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DOI：
10.1074/jbc.m109.006114
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发表时间：
2009-10-02
影响因子：
4.8
通讯作者：
Tsuge, Hideaki
中科院分区：
文献类型：
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作者：
Kobayashi, Hidetomo;Utsunomiya, Hiroko;Tsuge, Hideaki
众所周知，厌氧细菌Aeromonas sobria可引起潜在致命的感染性休克。我们最近提出，A. sobria 丝氨酸蛋白酶 (ASP) 是一种脓毒症相关因子，可诱导血管渗漏、通过激肽释放降低血压以及通过凝血酶原激活导致凝血。 ASP 优先切割二元氨基酸残基后面的肽键，Kex2（酿酒酵母丝氨酸蛋白酶）和弗林蛋白酶也是如此，它们是代表性的 Kexin 家族蛋白酶。在这里，我们使用反常散射的多重同晶置换方法以 1.65 埃分辨率揭示了 ASP 的晶体结构。尽管 ASP 的整体结构与 Kex2 相似，但它在靠近其活性位点处有一个独特的额外遮挡区域。此外，我们发现有切口的 ASP 变体在封闭区域内被切割。带切口的 ASP 显示出比天然酶更强的切割小肽底物的能力。另一方面，前激肽释放酶的裂解模式与 ASP 不同，表明封闭区域对于底物识别很重要。 ASP 的额外闭塞区域是独特的，可以作为促进新型抗菌药物开发的有用靶点。
The anaerobic bacterium Aeromonas sobria is known to cause potentially lethal septic shock. We recently proposed that A. sobria serine protease (ASP) is a sepsis-related factor that induces vascular leakage, reductions in blood pressure via kinin release, and clotting via activation of prothrombin. ASP preferentially cleaves peptide bonds that follow dibasic amino acid residues, as do Kex2 (Saccharomyces cerevisiae serine protease) and furin, which are representative kexin family proteases. Here, we revealed the crystal structure of ASP at 1.65 angstrom resolution using the multiple isomorphous replacement method with anomalous scattering. Although the overall structure of ASP resembles that of Kex2, it has a unique extra occluding region close to its active site. Moreover, we found that a nicked ASP variant is cleaved within the occluding region. Nicked ASP shows a greater ability to cleave small peptide substrates than the native enzyme. On the other hand, the cleavage pattern for prekallikrein differs from that of ASP, suggesting the occluding region is important for substrate recognition. The extra occluding region of ASP is unique and could serve as a useful target to facilitate development of novel antisepsis drugs.