Conversion of a non-selective adenosine receptor antagonist into A3-selective high affinity fluorescent probes using peptide-based linkers
作者:Andrea J. Vernall、Leigh A. Stoddart、Stephen J. Briddon、Hui Wen Ng、Charles A. Laughton、Stephen W. Doughty、Stephen J. Hill、Barrie Kellam
DOI:10.1039/c3ob41221k
日期:——
Advances in fluorescence-based imaging technologies have helped propel the study of real-time biological readouts and analysis across many different areas. In particular the use of fluorescent ligands as chemical tools to study proteins such as G protein-coupled receptors (GPCRs) has received ongoing interest. Methods to improve the efficient chemical synthesis of fluorescent ligands remain of paramount importance to ensure this area of bioanalysis continues to advance. Here we report conversion of the non-selective GPCR adenosine receptor antagonist Xanthine Amine Congener into higher affinity and more receptor subtype-selective fluorescent antagonists. This was achieved through insertion and optimisation of a dipeptide linker between the adenosine receptor pharmacophore and the fluorophore. Fluorescent probe 27 containing BODIPY 630/650 (pKD = 9.12 ± 0.05 [hA3AR]), and BODIPY FL-containing 28 (pKD = 7.96 ± 0.09 [hA3AR]) demonstrated clear, displaceable membrane binding using fluorescent confocal microscopy. From in silico analysis of the docked ligand-receptor complexes of 27, we suggest regions of molecular interaction that could account for the observed selectivity of these peptide-linker based fluorescent conjugates. This general approach of converting a non-selective ligand to a selective biological tool could be applied to other ligands of interest.
基于荧光的成像技术的进步推动了许多不同领域的实时生物读数和分析研究。特别是利用荧光配体作为化学工具来研究 G 蛋白偶联受体(GPCRs)等蛋白质,一直受到人们的关注。提高荧光配体化学合成效率的方法对于确保这一生物分析领域的持续发展至关重要。在此,我们报告了将非选择性 GPCR 腺苷受体拮抗剂黄嘌呤胺同系物转化为亲和力更高、受体亚型选择性更强的荧光拮抗剂的情况。这是通过在腺苷受体药效团和荧光团之间插入和优化二肽连接体实现的。含有 BODIPY 630/650 的荧光探针 27(pKD = 9.12 ± 0.05 [hA3AR])和含有 BODIPY FL 的探针 28(pKD = 7.96 ± 0.09 [hA3AR])在荧光共聚焦显微镜下显示出清晰、可置换的膜结合。通过对 27 的配体-受体对接复合物进行硅学分析,我们提出了分子相互作用的区域,这些区域可能是这些基于肽连接体的荧光共轭物具有选择性的原因。这种将非选择性配体转化为选择性生物工具的一般方法可应用于其他感兴趣的配体。