Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital, Department of Biomedical Engineering, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, P. R. China.
Nanobiomedical Center, School of Life Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot, 010018, P. R. China.
Chembiochem. 2019 Sep 16;20(18):2324-2330. doi: 10.1002/cbic.201900166. Epub 2019 Jul 29.
Amino acids are natural choices as building blocks when developing biofunctional entities owing to their superior diversity and versatile physicochemical properties compared to nucleotide bases. A simple permutation of the amino acids creates a broad palette of proteins and these have been successfully engineered into useful biofunctional agents. For example, the intrinsic ultraviolet fluorescence of phenylalanine and tryptophan has been engineered to emit in the visible spectrum, which has broad applications for imaging/sensing probes, photothermal therapy agents, optogenetic switches, etc. Nature produces more colorful coats/furs, feathers/hairs, and eyes through various biochemical modifications of tyrosine-based pigmentation. However, it is challenging to modulate the fluorescence wavelength from the UV to the visible region through oligopeptides. Herein, we report an innovative approach to obtain cyan fluorescence by using de novo tripeptides containing glycine, tyrosine, and lysine, which form robust dimer structures under moderate oxidizing conditions. Through an in vitro mutation approach, we deduce that both the amino acids and their sequence play significant roles in modulating the fluorescence. We believe this work holds great promise for developing novel cell imaging and resonance energy-transfer-based fluorescent probes.
与核苷酸碱基相比，氨基酸具有优越的多样性和多功能物理化学性质，因此是开发生物功能实体的理想构建模块。通过简单地排列氨基酸，就可以创造出丰富多彩的蛋白质，并且这些蛋白质已经成功地被设计成有用的生物功能试剂。例如，苯丙氨酸和色氨酸的固有紫外荧光已被设计为在可见光谱中发射，这在成像/传感探针、光热治疗剂、光遗传学开关等方面有广泛的应用。自然界通过酪氨酸基色素的各种生化修饰产生了更多丰富多彩的外套/皮毛、羽毛/毛发和眼睛。然而，通过寡肽将荧光波长从紫外区调至可见区具有挑战性。在此，我们报告了一种通过使用含有甘氨酸、酪氨酸和赖氨酸的全新三肽获得青绿色荧光的创新方法，这些三肽在适度氧化条件下形成稳定的二聚体结构。通过体外突变方法，我们推断出氨基酸及其序列在调节荧光方面都起着重要作用。我们相信这项工作在开发新型细胞成像和共振能量转移荧光探针方面具有很大的潜力。
