Evidence for multiple modes of neutrophil serine protease recognition by the EAP family of Staphylococcal innate immune evasion proteins.
Evidence for multiple modes of neutrophil serine protease recognition by the EAP family of Staphylococcal innate immune evasion proteins.
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葡萄球菌先天免疫逃避蛋白 EAP 家族识别中性粒细胞丝氨酸蛋白酶多种模式的证据。
DOI：
10.1002/pro.3342
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Geisbrecht,BrianV
中科院分区：
文献类型：
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作者：
Stapels,DaphneAC;Woehl,JordanL;Milder,FinJ;Tromp,AngelinoT;vanBatenburg,AernoudA;deGraaf,WilcoC;Broll,SamuelC;White,NatalieM;Rooijakkers,SuzanHM;Geisbrecht,BrianV
中性粒细胞在其亲天青颗粒中含有高水平的胰凝乳酶样丝氨酸蛋白酶(NSP)，这些颗粒在免疫系统中具有多种功能。作为回应，致病金黄色葡萄球菌已经进化出三种有效的抑制剂(EAP、EapH1和EapH2)，以保护细菌及其分泌的几种毒力因子免受NSP的降解作用。我们以前发现，这些所谓的EAP结构域蛋白代表了一类新的NSP抑制剂，其特征是非共价抑制机制和独特的靶标特异性。基于EAP蛋白和NSP之间高度的结构同源性以及支持的生化数据，我们预测所有EAP/NSP对的抑制复合体都将是相似的。然而，我们在这里提供的证据表明，EapH1和EapH2以不同的方向与典型的NSP-中性粒细胞弹性蛋白酶(NE)结合。我们发现，EapH1/NE界面EapH1残基的改变导致NE亲和力的急剧丧失和抑制，而EapH2等位突变对NE的结合或抑制没有影响。令人惊讶的是，EapH2一个完全不同区域的残基突变严重影响了EapH2的NE结合和抑制特性。尽管EapH1和EapH2同样很好地结合和抑制NE和第二个NSP，组织蛋白酶G，但这两种蛋白都不能与结构上相关但非蛋白水解性颗粒蛋白天青素相互作用。这些研究扩大了我们对EAP/NSP相互作用的理解，并表明这个免疫逃避蛋白家族的成员具有不同的靶标识别模式。
Neutrophils contain high levels of chymotrypsin‐like serine proteases (NSPs) within their azurophilic granules that have a multitude of functions within the immune system. In response, the pathogenStaphylococcus aureushas evolved three potent inhibitors (Eap, EapH1, and EapH2) that protect the bacterium as well as several of its secreted virulence factors from the degradative action of NSPs. We previously showed that these so‐called EAP domain proteins represent a novel class of NSP inhibitors characterized by a non‐covalent inhibitory mechanism and a distinct target specificity profile. Based upon high levels of structural homology amongst the EAP proteins and the NSPs, as well as supporting biochemical data, we predicted that the inhibited complex would be similar for all EAP/NSP pairs. However, we present here evidence that EapH1 and EapH2 bind the canonical NSP, Neutrophil Elastase (NE), in distinct orientations. We discovered that alteration of EapH1 residues at the EapH1/NE interface caused a dramatic loss of affinity and inhibition of NE, while mutation of equivalent positions in EapH2 had no effect on NE binding or inhibition. Surprisingly, mutation of residues in an altogether different region of EapH2 severely impacted both the NE binding and inhibitory properties of EapH2. Even though EapH1 and EapH2 bind and inhibit NE and a second NSP, Cathepsin G, equally well, neither of these proteins interacts with the structurally related, but non‐proteolytic granule protein, azurocidin. These studies expand our understanding of EAP/NSP interactions and suggest that members of this immune evasion protein family are capable of diverse target recognition modes.