N-terminal residues of the chemotaxis inhibitory protein of Staphylococcus aureus are essential for blocking formylated peptide receptor but not C5a receptor
N-terminal residues of the chemotaxis inhibitory protein of Staphylococcus aureus are essential for blocking formylated peptide receptor but not C5a receptor
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DOI：
10.4049/jimmunol.173.9.5704
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发表时间：
2004-11-01
影响因子：
4.4
通讯作者：
van Strijp, JAG
中科院分区：
文献类型：
--
作者：
Haas, PJ;de Haas, CJC;van Strijp, JAG
金黄色葡萄球菌分泌一种同时作用于C5aR和甲酰化肽受体(FPR)的因子。这种金黄色葡萄球菌趋化抑制蛋白(CHIPS)可阻断C5a和fMLP诱导的吞噬细胞活化和趋化。抗芯片的单抗完全抑制芯片对一种受体的活性，而不影响另一种受体，表明两个不同的位点对两种作用都负责。由CHIP衍生的N-末端6-AA多肽能够模拟CHIP的抗FPR特性，但对C5aR没有影响。合成肽中的前6个氨基酸分别取代了所有其他自然产生的氨基酸，表明第一个和第三个残基在阻断FPR方面起着重要作用。利用大肠杆菌表达系统，我们创造了突变的CHIP蛋白，其中这些氨基酸被取代。这些突变蛋白损伤或缺失了FPR-，但仍具有完整的C5aR阻断活性，表明FPR阻断活性的丧失不是由任何结构损伤引起的。这确定了第一种和第三种氨基酸，都是苯丙氨酸，对于阻止fMLP诱导的吞噬细胞激活的芯片是必不可少的。芯片能够以高亲和力(k(D)=35.4+/-7.7 nM)特异性地抑制FPR，这可能是一种重要的新工具，可以进一步刺激对FPR潜在机制及其在疾病过程中的作用的基础研究。
Staphylococcus aureus excretes a factor that specifically and simultaneously acts on the C5aR and the formylated peptide receptor (FPR). This chemotaxis inhibitory protein of S. aureus (CHIPS) blocks C5a- and fMLP-induced phagocyte activation and chemotaxis. Monoclonal anti-CHIPS Abs inhibit CHIPS activity against one receptor completely without affecting the other receptor, indicating that two distinct sites are responsible for both actions. A CHIPS-derived N-terminal 6 aa peptide is capable of mimicking the anti-FPR properties of CHIPS but has no effect on the C5aR. Synthetic peptides in which the first 6 aa are substituted individually for all other naturally occurring amino acids show that the first and third residue play an important role in blocking the FPR. Using an Escherichia coli expression system, we created mutant CHIPS proteins in which these amino acids are substituted. These mutant proteins have impaired or absent FPR- but still an intact C5aR-blocking activity, indicating that the loss of the FPR-blocking activity is not caused by any structural impairment. This identifies the first and third amino acid, both a phenylalanine, to be essential for CHIPS blocking the fMLP-induced activation of phagocytes. The unique properties of CHIPS to specifically inhibit the FPR with high affinity (k(d) = 35.4 +/- 7.7 nM) could be an important new tool to further stimulate the fundamental research on the mechanisms underlying the FPR and its role in disease processes.