State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, PR China.
Chemistry. 2012 Nov 5;18(45):14520-6. doi: 10.1002/chem.201201606. Epub 2012 Sep 24.
Thiol-containing amino acids (aminothiols) such as cysteine (Cys) and homocysteine (Hcy) play a key role in various biological processes including maintaining the homeostasis of biological thiols. However, abnormal levels of aminothiols are associated with a variety of diseases. The native chemical ligation (NCL) reaction has attracted great attention in the fields of chemistry and biology. NCL of peptide segments involves cascade reactions between a peptide-α-thioester and an N-terminal cysteine peptide. In this work, we employed the NCL reaction mechanism to formulate a Förster resonance energy transfer (FRET) strategy for the design of ratiometric fluorescent probes that were selective toward aminothiols. On the basis of this new strategy, the ratiometric fluorescent probe 1 for aminothiols was judiciously designed. The new probe is highly selective toward aminothiols over other thiols and exhibits a very large variation (up to 160-fold) in its fluorescence ratio (I(458)/I(603)). The new fluorescent probe is capable of ratiometric detection of aminothiols in newborn calf and human serum samples and is also suitable for ratiometric fluorescent imaging of aminothiols in living cells.
含巯基的氨基酸（巯基氨基酸），如半胱氨酸（Cys）和高半胱氨酸（Hcy），在包括维持生物巯基的内稳态在内的各种生物过程中发挥关键作用。然而，异常水平的巯基氨基酸与多种疾病有关。天然化学连接（NCL）反应在化学和生物学领域引起了极大关注。肽段的 NCL 反应涉及肽-α-硫酯和 N 端半胱氨酸肽之间的级联反应。在这项工作中，我们采用 NCL 反应机制，制定了用于设计对巯基氨基酸具有选择性的比率型荧光探针的福斯特共振能量转移（FRET）策略。基于这一新策略，我们巧妙设计了用于检测巯基氨基酸的比率型荧光探针 1。与其他巯基相比，该新探针对巯基氨基酸具有很高的选择性，其荧光强度比（I(458)/I(603)）变化很大（高达 160 倍）。新的荧光探针能够在新生牛犊和人血清样本中进行比率型检测巯基氨基酸，并且还适用于活细胞中巯基氨基酸的比率型荧光成像。
