Nabi A H M Nurun, Biswas Kazal Boron, Nakagawa Tsutomu, Ichihara Atsuhiro, Inagami Tadashi, Suzuki Fumiaki
Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Biochim Biophys Acta. 2009 Dec;1794(12):1838-47. doi: 10.1016/j.bbapap.2009.08.024. Epub 2009 Sep 3.
An important role of the decoy peptide sequence has recently been suggested in vitro for the binding of prorenin to the (pro)renin receptor [PRR]. In this study, other prospective crucial regions in renin and prorenin responsible for their interaction with PRR were investigated using various kinds of peptides, e.g., the "hinge" S149QGVLKEDVF158 designed from the structure of renin also common to prorenin, L1PPTDTTTF8P, L1PPTDTTTFKRIFLKR15P and the decoy (R10PIFLKRMPSI19P) designed from the predicted structure of prorenin. For the kinetic analysis, the recombinant hPRR was immobilized on the biosensor surface through a specific anti-PRR antibody. In case of the equilibrium state analysis, the PRR was directly adsorbed on plastic wells for observing the bindings of renin/prorenin. The dissociation constants (KD) for the bindings of renin and prorenin to the pre-adsorbed receptors were 4.5 and 1.0 nM, respectively, similar to those stated in the kinetic study by BIAcore assay. The "hinge" region peptide bound to PRR in a dose-dependent manner with a KD estimated 17.0 nM which was five times higher than that of the decoy. The KD values for L1PPTDTTTF8P and L1PPTDTTTFKRIFLKR15P were 52 and 7.6 nM, respectively. The "hinge" peptide, as the decoy, inhibited the bindings of renin and prorenin to PRR. The inhibition constant (Ki) for the binding of renin and prorenin by the decoy and "hinge" were 16.7 and 15.1, and 37.1 and 30.7 nM, respectively. These in vitro studies suggest that renin has a single and prorenin has at least two high affinity binding sites for the PRR.
最近有研究表明，诱饵肽序列在体外对肾素原与（前）肾素受体[PRR]的结合起着重要作用。在本研究中，使用了各种肽来研究肾素和肾素原中其他可能与PRR相互作用的关键区域，例如，从肾素结构（肾素原也具有该结构）设计的“铰链区”S149QGVLKEDVF158、L1PPTDTTTF8P、L1PPTDTTTFKRIFLKR15P以及从肾素原预测结构设计的诱饵肽（R10PIFLKRMPSI19P）。为进行动力学分析，通过特异性抗PRR抗体将重组人PRR固定在生物传感器表面。在平衡状态分析中，将PRR直接吸附在塑料孔中以观察肾素/肾素原的结合情况。肾素和肾素原与预吸附受体结合的解离常数（KD）分别为4.5和1.0 nM，与BIAcore分析动力学研究中所述的值相似。“铰链区”肽以剂量依赖方式与PRR结合，估计KD为17. nM，比诱饵肽高五倍。L1PPTDTTTF8P和L1PPTDTTTFKRIFLKR15P的KD值分别为52和7.6 nM。“铰链区”肽作为诱饵，抑制了肾素和肾素原与PRR的结合。诱饵肽和“铰链区”肽对肾素和肾素原结合的抑制常数（Ki）分别为16.7和15.1，以及37.1和30.7 nM。这些体外研究表明，肾素对PRR有一个高亲和力结合位点，而肾素原至少有两个高亲和力结合位点。
