STRUCTURAL REQUIREMENTS FOR THE OCCUPANCY OF PITUITARY ADENYLATE-CYCLASE-ACTIVATING-PEPTIDE (PACAP) RECEPTORS AND ADENYLATE-CYCLASE ACTIVATION IN HUMAN NEUROBLASTOMA NB-OK-1 CELL-MEMBRANES - DISCOVERY OF PACAP(6-38) AS A POTENT ANTAGONIST
STRUCTURAL REQUIREMENTS FOR THE OCCUPANCY OF PITUITARY ADENYLATE-CYCLASE-ACTIVATING-PEPTIDE (PACAP) RECEPTORS AND ADENYLATE-CYCLASE ACTIVATION IN HUMAN NEUROBLASTOMA NB-OK-1 CELL-MEMBRANES - DISCOVERY OF PACAP(6-38) AS A POTENT ANTAGONIST
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DOI：
10.1111/j.1432-1033.1992.tb17043.x
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发表时间：
1992-07-01
期刊：
影响因子：
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通讯作者：
CHRISTOPHE, J
中科院分区：
文献类型：
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作者：
ROBBERECHT, P;GOURLET, P;CHRISTOPHE, J
在这些结构活性研究中，垂体腺苷酸环化酶激活肽的27-氨基酸形式PACAP（1 - 27）和38-氨基酸形式PACAP（1 - 38）的46个类似物在1 - 3、20和21位被单取代或双取代，或N-末端缩短。在人神经母细胞瘤NB-OK-1细胞膜上比较所有类似物占据I-125-[AcHis 1]PACAP（1 - 27）标记的受体（AcHis，N（α）-乙酰组氨酸）和激活腺苷酸环化酶（就效力和内在活性而言）的能力。两个参数的剂量/效应曲线的单相斜率表明与一类PACAP受体相互作用。C-末端延伸肽PACAP（1 - 38）中的残基28-38在识别中起有利作用，因为与腺苷酸环化酶偶联的受体通常对PACAP（1 - 38）类似物比对相应的PACAP（1 - 27）类似物更敏感。与PACAP（6 - 27）不同的是，PACAP（6 - 38）被公认为是一种有效的竞争性拮抗剂（K（i）1.5 nM）。残基1 - 3在酶激活中都很重要：β-转角电位的修饰产生完全激动剂（LAla 2和DAla 2衍生物）或部分激动剂（LPhe 2和DPhe 2; LAg 2和DArg 2; Glu 3和Asn 3）。最后，适当的α-螺旋也很重要：Gly 21/Gly 22对Lys 21/Lys 22的组合取代急剧降低了结合亲和力。
In these structure activity studies, the 46 analogs of the 27-amino-acid form of the pituitary-adenylate-cyclase-activating peptide, PACAP(1 - 27), and the 38-amino-acid form, PACAP(1 - 38), were either monosubstituted or bisubstituted at positions 1 - 3, 20 and 21 or N-terminally shortened. All analogs were compared on human neuroblastoma NB-OK-1 cell membranes for their ability to occupy I-125-[AcHis1]PACAP(1 -27)-labelled receptors (AcHis, N(alpha)-acetylhistidine) and to activate adenylate cyclase (in terms of potency and intrinsic activity). The monophasic slope of dose/effect curves on both parameters suggested interaction with one class of PACAP receptor. Residues 28-38 in the C-terminally extended peptide, PACAP(1 - 38), played a favorable role in recognition, in that receptors coupled to adenylate cyclase were, in general, more sensitive to PACAP(1 - 38) analogs than to the corresponding PACAP(1 - 27) analogs. At variance with PACAP(6 - 27), PACAP(6 - 38) was well recognized and acted as a potent competitive antagonist (K(i) 1.5 nM).Residues 1 - 3 were all important in enzyme activation: modification of the beta-turn potential gave full agonists (the LAla2 and DAla2 derivatives) or partial agonists (LPhe2 and DPhe2; LArg2 and DArg2; Glu3 and Asn3). Finally, a proper alpha-helix was also important: the combined substitution of Lys21/Lys22 by Gly21/Gly22 decreased the binding affinity sharply.