Structure of the Tyrosine-sulfated C5a Receptor N Terminus in Complex with Chemotaxis Inhibitory Protein of Staphylococcus aureus
Structure of the Tyrosine-sulfated C5a Receptor N Terminus in Complex with Chemotaxis Inhibitory Protein of Staphylococcus aureus
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DOI：
10.1074/jbc.m808179200
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发表时间：
2009-05-01
影响因子：
4.8
通讯作者：
Kemmink, Johan
中科院分区：
文献类型：
--
作者：
Ippel, Johannes H.;de Haas, Carla J. C.;Kemmink, Johan
补体成分C5 a是诱导白细胞向感染和损伤部位趋化的有效促炎剂。C5 a通过其G蛋白偶联的C5 a受体（C5 aR）介导其作用。虽然在正常条件下非常有益，但过量的C5 a水平可能对宿主有害，并且与许多炎性疾病有关。C5 aR的天然抑制剂是金黄色葡萄球菌的趋化性抑制蛋白（CHIPS）。CHIPS是由沙门氏菌分泌的一种121个残基的蛋白。金黄色。它以纳摩尔亲和力结合C5 aR的N末端（残基1-35），从而有效抑制人白细胞中C5 a介导的应答。因此，CHIPS为开发新的抗炎药提供了一个起点。位于C5 aR N端11和14位的两个O-硫酸化酪氨酸残基在C5 a的识别中起关键作用，但它们在CHIPS结合中的作用迄今尚未确定。通过等温滴定量热法，使用合成的Tyr-11-和Tyr-14-硫酸化和非硫酸化C5 aR N-末端肽，我们证明了硫酸基团对于C5 aR和CHIPS之间的紧密结合是必不可少的。此外，CHIPS和硫酸化C5 aR N-末端肽的复合物的NMR结构揭示了精确的结合基序以及硫酸化酪氨酸残基sY 11和sY 14的不同作用。这些结果为设计基于CHIPS的新型C5 aR抑制剂提供了分子框架。
Complement component C5a is a potent pro-inflammatory agent inducing chemotaxis of leukocytes toward sites of infection and injury. C5a mediates its effects via its G protein-coupled C5a receptor (C5aR). Although under normal conditions highly beneficial, excessive levels of C5a can be deleterious to the host and have been related to numerous inflammatory diseases. A natural inhibitor of the C5aR is chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS). CHIPS is a 121-residue protein excreted by S. aureus. It binds the N terminus of the C5aR (residues 1-35) with nanomolar affinity and thereby potently inhibits C5a-mediated responses in human leukocytes. Therefore, CHIPS provides a starting point for the development of new anti-inflammatory agents. Two O-sulfated tyrosine residues located at positions 11 and 14 within the C5aR N terminus play a critical role in recognition of C5a, but their role in CHIPS binding has not been established so far. By isothermal titration calorimetry, using synthetic Tyr-11-and Tyr-14-sulfated and non-sulfated C5aR N-terminal peptides, we demonstrate that the sulfate groups are essential for tight binding between the C5aR and CHIPS. In addition, the NMR structure of the complex of CHIPS and a sulfated C5aR N-terminal peptide reveals the precise binding motif as well as the distinct roles of sulfated tyrosine residues sY11 and sY14. These results provide a molecular framework for the design of novel CHIPS-based C5aR inhibitors.