Residues 21-30 within the extracellular N-terminal region of the C5a receptor represent a binding domain for the C5a anaphylatoxin
Residues 21-30 within the extracellular N-terminal region of the C5a receptor represent a binding domain for the C5a anaphylatoxin
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DOI：
10.1074/jbc.273.17.10411
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发表时间：
1998-04-24
影响因子：
4.8
通讯作者：
Ni, F
中科院分区：
文献类型：
--
作者：
Chen, ZG;Zhang, XL;Ni, F
C5a 过敏毒素的功能是通过其与具有七个跨膜螺旋的细胞表面受体的相互作用来表达的。 C5a 与受体的相互作用已通过双位点模型进行了解释，其中 C5a 上的识别和效应位点分别结合到受体上的识别和效应结构域，导致受体激活（Chenoweth, D. E. 和 Hugli, T. E. (1980) Mel.Immunol. 17, 151-161。此外，C5a 受体的胞外 N 端区域被认为是 C5a 受体的识别结构域。 C5a，负责类似于 C5a-受体复合物的 50% 的结合能 (Mery, L., and Boulay, F. (1994) J. Biol. Chem. 269, 3457-3463 ；DeMartino, J. A., Van Riper, G., Siciliano, S. J., Molineaux, C. J., Konteatis, Z. D., Rosen, H. 和 Springer, M. S. (1994) J. Biol. 269, 14446-14450) 在这项工作中，通过使用重组人 C5a 分子和肽片段检查了 C5a 与 C5a 受体 N 端结构域的相互作用。 M(1)NSFN(5)YTTPD(10)YGHYD(15)DKDTL(20)DLNTP(25)VDKTS(30)NTLR(hC5aRF-1-34)、乙酰基-HYD15DKDTL20DLNTP25VDKTS30NTLR(hC5aRF-13-34)，和源自人 C5a 受体的乙酰基-TL20DLNTP25VDKTS30N-酰胺 (hC5aRF-19-31) 受体片段和 C5a 分子的 NMR 谱中的结合诱导共振扰动表明，C5a 受体的分离的 N 端结构域或残基 1-34 保留了与 C5a 和完整 C5a 中缺乏激动性 C 端尾部的 C5a 类似物的特异性结合。受受体肽的结合扰动的 C5a 残基位于 C5a 结构的螺旋核心内，与使用突变的 C5a 和完整受体分子的功能研究结果一致。所有三种受体肽 hC5aRF-1-34、hC5aRF-13-34 和 hC5aRF-19-31 通过包含任一的 21-30 区域对 C5a 的结合做出反应。疏水性、极性或带正电荷的残基，例如 Thr(24)、Pro(25)、Val(26)、Lys(28)、Thr(29) 和 Ser(30)。发现所有三个受体片段的 21-30 片段在溶液中均具有部分折叠构象，与残基 1-18 无关。这些结果表明，C5a 受体 N 末端的短肽序列或残基 21-30 可能构成C5a 上识别位点的结合域。
The functions of the C5a anaphylatoxin are expressed through its interaction with a cell-surface receptor with seven transmembrane helices. The interaction of C5a with the receptor has been explained by a two-site model whereby recognition and effector sites on C5a bind, respectively, to recognition and effector domains on the receptor, leading to receptor activation (Chenoweth, D. E., and Hugli, T. E. (1980) Mel. Immunol. 17, 151-161. In addition, the extracellular N-terminal region of the C5a receptor has been implicated as the recognition domain for C5a, responsible for similar to 50% of the binding energy of the C5a-receptor complex (Mery, L., and Boulay, F. (1994) J. Biol. Chem. 269, 3457-3463; DeMartino, J. A., Van Riper, G., Siciliano, S. J., Molineaux, C. J., Konteatis, Z. D., Rosen, H., and Springer, M. S. (1994) J. Biol. Chem. 269, 14446-14450). In this work, the interactions of C5a with the N-terminal domain of the C5a receptor were examined by use of recombinant human C5a molecules and peptide fragments M(1)NSFN(5)YTTPD(10)YGHYD(15)DKDTL(20)DLNTP(25)VDKTS(30)NTLR(hC5aRF-1-34), acetyl-HYD15DKDTL20DLNTP25VDKTS30NTLR (hC5aRF-13-34), and acetyl-TL20DLNTP25VDKTS30N-amide (hC5aRF-19-31) derived from human C5a receptor. Binding induced resonance perturbations in the NMR spectra of the receptor fragments and the C5a molecules indicated that the isolated N-terminal domain or residues 1-34 of the C5a receptor retain specific binding to C5a and to a C5a analog devoid of the agonistic C-terminal tail in the intact C5a. Residues of C5a perturbed by the binding of the receptor peptides are localized within the helical core of the C5a structure, in agreement with the results from functional studies employing mutated C5a and intact receptor molecules. All three receptor peptides, hC5aRF-1-34, hC5aRF-13-34, and hC5aRF-19-31, responded to the binding of C5a through the 21-30 region containing either hydrophobic, polar, or positively charged residues such as Thr(24),Pro(25), Val(26), Lys(28), Thr(29), and Ser(30). The 21-30 segment of all three receptor fragments was found to have a partially folded conformation in solution, independent of residues 1-18. These results indicate that a short peptide sequence, or residues 21-30, of the C5a receptor N terminus may constitute the binding domain for the recognition site on C5a.