Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology , Tianjin 300457, China.
Anal Chem. 2017 Oct 3;89(19):10431-10438. doi: 10.1021/acs.analchem.7b02430. Epub 2017 Sep 14.
Glucose assay is of great scientific significance in clinical diagnostics and bioprocess monitoring, and to design a new glucose receptor is necessary for the development of more sensitive, selective, and robust glucose detection techniques. Herein, a series of cyclic peptide (CP) glucose receptors were designed to mimic the binding sites of glucose binding protein (GBP), and CPs' sequence contained amino acid sites Asp, Asn, His, Asp, and Arg, which constituted the first layer interactions of GBP. The properties of these CPs used as a glucose receptor or substitute for the GBP were studied by using a quartz crystal microbalance (QCM) technique. It was found that CPs can form a self-assembled monolayer at the Au quartz electrode surface, and the monolayer's properties were characterized by using cyclic voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. The CPs' binding affinity to saccharide (i.e., galactose, fructose, lactose, sucrose, and maltose) was investigated, and the CPs' sensitivity and selectivity toward glucose were found to be dependent upon the configuration,i.e., the amino acids sequence of the CPs. The cyclic unit with a cyclo[-CNDNHCRDNDC-] sequence gave the highest selectivity and sensitivity for glucose sensing. This work suggests that a synthetic peptide bearing a particular functional sequence could be applied for developing a new generation of glucose receptors and would find huge application in biological, life science, and clinical diagnostics fields.
葡萄糖检测在临床诊断和生物过程监测中具有重要的科学意义，设计新型葡萄糖受体对于开发更灵敏、选择性更强、更稳健的葡萄糖检测技术是必要的。在此，我们设计了一系列环肽（CP）葡萄糖受体，以模拟葡萄糖结合蛋白（GBP）的结合位点。CP 的序列中包含氨基酸位点天冬氨酸（Asp）、天冬酰胺（Asn）、组氨酸（His）、天冬氨酸（Asp）和精氨酸（Arg），它们构成了 GBP 的第一层相互作用。我们使用石英晶体微天平（QCM）技术研究了这些 CP 作为葡萄糖受体或 GBP 替代物的性能。结果发现，CP 可以在 Au 石英电极表面形成自组装单层，并且可以通过循环伏安法、电化学阻抗谱和原子力显微镜对单层的性质进行表征。我们还研究了 CP 与糖（即半乳糖、果糖、乳糖、蔗糖和麦芽糖）的结合亲和力，发现 CP 对葡萄糖的敏感性和选择性取决于其构型，即 CP 的氨基酸序列。具有环[-CNDNHCRDNDC-]序列的环肽单元对葡萄糖检测具有最高的选择性和灵敏度。这项工作表明，具有特定功能序列的合成肽可用于开发新一代葡萄糖受体，并将在生物、生命科学和临床诊断领域得到广泛应用。
