多肽荧光探针特异性识别细胞中的Cu^(2+)和Cys

A novel fluorescent peptide probe for the specific detection of Cu^(2+) and Cys in cells

Cu^(2+)作为生物体内含量第三多的必需微量金属元素,在生物体新陈代谢和正常的生命活动中扮演着重要角色,而体内Cu^(2+)的过度积累可能是唐氏综合征、阿尔兹海默症等许多疾病的关键诱因.Cys作为生物体内不可或缺的氨基酸,参与调控体内蛋白质的合成、翻译后修饰等基本的生理过程,它的富集可能会引起神经中毒、肝脏损伤、肾结石等疾病.因此,实现Cu^(2+)和Cys的高效检测对相关疾病的机理研究和治疗至关重要.本文利用赖氨酸侧链的两个氨基,与多肽序列中的天冬氨酸反应,成功合成了发夹式的多肽荧光探针P((Dansyl-Glu-Asp)2-Lys)).研究发现,多肽荧光探针P通过荧光淬灭效应可以高特异性地识别溶液中的Cu^(2+),而不受其他金属离子的干扰;并以1:1的比例结合形成P-Cu平台,该平台可以高选择性地检测Cys.实验结果表明,多肽荧光探针P可以"OnOff-On"型响应模式实现对Cu^(2+)和Cys的高灵敏检测,检测限分别为52和43 nmol/L.并且,多肽荧光探针P可成功用于He La细胞中Cu^(2+)和Cys的成像.这种新型多肽荧光探针P具有优秀的生物相容性、较低的细胞毒性等优点,可以用于活细胞中Cu^(2+)和Cys的特异性检测,为Cu^(2+)和Cys相关疾病的治疗和诊断提供新的手段.

As the third most abundant essential trace elements in the organism,Cu^(2+) plays an important role in normal physiological activities and metabolism,while excessive Cu^(2+) has been found to be closely related to serious diseases such as Down’s syndrome and Alzheimer’s disease.As an indispensable amino acid in the organism,Cys participates in the regulation of protein synthesis,post-translational modification and other biological functions.However,its pronounced accumulation may cause neurotoxicity,liver damage,kidney stones and other diseases.Therefore,the development of efficient assays for Cu^(2+) and Cys is critical for the diagnosis and treatment of these diseases.We have synthesized a hairpin type fluorescent peptide probe P((Dansyl-Glu-Asp)2-Lys)by using two amino groups in the side chain of lysine to react with aspartic acid in the peptide sequence.We found that the peptide probe P can highly specifically detect Cu^(2+) by fluorescence quenching without the interferences of other metal ions.The formation of P-Cu biosensor at 1:1 stoichiometry can highly selectively detect Cys and recover its fluorescence.We have demonstrated that the fluorescent peptide probe P provides an“On-Off-On”sensing mode for Cu^(2+) and Cys with detection limits of 52 and 43 nM,respectively.The fluorescent peptide probe P has been successfully used for the imaging of Cu^(2+) and Cys in HeLa cells.The newly developed fluorescent peptide probe P has extraordinary features such as good biocompatibility,low biotoxicity,and high specificity of Cu^(2+) and Cys,which shows new detection method in the studies of various Cu^(2+)/Cys-involved diseases.