SAR1-P-BENZOYLPHENYLALANINE-ANGIOTENSIN, A NEW PHOTOAFFINITY PROBE FOR SELECTIVE LABELING OF THE TYPE-2 ANGIOTENSIN RECEPTOR
SAR1-P-BENZOYLPHENYLALANINE-ANGIOTENSIN, A NEW PHOTOAFFINITY PROBE FOR SELECTIVE LABELING OF THE TYPE-2 ANGIOTENSIN RECEPTOR
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DOI：
10.1016/0167-0115(93)90245-4
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发表时间：
1993-03-19
影响因子：
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通讯作者：
ESCHER, E
中科院分区：
文献类型：
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作者：
BOSSE, R;SERVANT, G;ESCHER, E
以前的光亲和标记血管紧张素II（Ang）受体与azidophenylalanine含有Ang类似物产生高产率标记的60 kDa的蛋白质对牛肾上腺皮质膜。该制剂主要富集1型Ang受体（AT 1），并且AT 1选择性配体（L158，809）完全阻止标记，因此证实了标记蛋白的AT 1性质。我们尝试用[Sar 1，D-Phe（N3）8]Ang光标记人子宫肌层的2型Ang受体（AT 2）是不成功的，揭示了高度的光标记选择性。合成了含有光敏氨基酸对苯甲酰苯丙氨酸（Bpa）的血管紧张素类似物[Sar 1，Bpa 8]Ang（或BpaAng）。该化合物在兔主动脉上是特异性但非竞争性的Ang拮抗剂，pA 2为8.5。它对牛肾上腺皮质膜（K（d）= 6.5 nM）（主要是AT 1制剂）和人子宫肌膜（K（d）= 0.39 nM）（主要是AT 2制剂）显示出良好的结合亲和力。碘化BpaAng的光标记实验表明，AT 1未被共价标记，而AT 2被高收率地共价标记。用AT 2选择性配体PD 123319和AT 1选择性拮抗剂L158，809验证标记特异性。我们的结果表明，I-125-BpaAng是专门标记AT 2位点。这种化合物应该是一个有用的工具，进一步的AT 2结合位点的生化表征。
Previous photoaffinity labeling of angiotensin II (Ang) receptors with azidophenylalanine containing Ang analogs produced high yield labeling of a 60 kDa protein on bovine adrenocortical membranes. This preparation is mostly enriched in the type 1 Ang receptor (AT1) and AT1 selective ligands (L158,809) totally prevented labeling, therefore confirming the AT1 nature of the labeled protein. Our attempt to photolabel the type 2 Ang receptor (AT2) of human myometrium with [Sar1,D-Phe(N3)8]Ang was unsuccessful, revealing a high degree of photolabeling selectivity. An Ang analog, [Sar1,Bpa8]Ang (or BpaAng) was prepared containing the photosensitive amino acid p-benzoylphenylalanine (Bpa). This compound was a specific but non-competitive Ang antagonist on rabbit aorta with a pA2 of 8.5. It displayed good binding affinities for bovine adrenocortical membranes (K(d) = 6.5 nM), a predominantly AT1 preparation, and for human myometrium membranes (K(d) = 0.39 nM), a predominantly AT2 preparation. Photolabeling experiments with iodinated BpaAng showed that AT1 was not covalently labeled whereas AT2 was covalently labeled with high yield. Labeling specificity was verified with the AT2-selective ligand PD123319 and with the AT1-selective antagonist L158,809. Our results indicate that I-125-BpaAng is exclusively labeling AT2 sites. This compound should be a useful tool for further biochemical characterization of the AT2 binding site.