Ruchkin D A, Gavrikov A S, Kolesov D V, Gorokhovatsky A Yu, Chepurnykh T V, Mishin A S, Maksimov E G, Pletneva N V, Pletnev V Z, Pavlova A M, Nikitin V A, Bogdanov A M
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, 117997 Russia.
Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow,119992 Russia.
Acta Naturae. 2025 Apr-Jun;17(2):110-117. doi: 10.32607/actanaturae.27545.
Red fluorescent proteins (RFPs) are often probes of choice for living tissue microscopy and whole-body imaging. When choosing a specific RFP variant, the priority may be given to the fluorescence brightness, maturation rate, monomericity, excitation/emission wavelengths, and low toxicity, which are rarely combined in an optimal way in a single protein. If additional requirements such as prolonged fluorescence lifetime and/or blinking ability are applied, the available repertoire of probes could dramatically narrow. Since the entire diversity of conventional single-component RFPs belongs to just a few phylogenetic lines (DsRed-, eqFP578- and eqFP611-derived being the major ones), it is not unexpected that their advantageous properties are split between close homologs. In such cases, a systematic mutagenetic analysis focusing on variant-specific amino acid residues can shed light on the origins of the distinctness between related RFPs and may aid in consolidating their strengths in new RFP variants. For instance, the protein FusionRed, despite being efficient in fluorescence labeling thanks to its good monomericity and low cytotoxicity, has undergone considerable loss in fluorescence brightness/lifetime compared to the parental mKate2. In this contribution, we describe a fast-maturing monomeric RFP designed semi-rationally based on the mKate2 and FusionRed templates that outperforms both its parents in terms of molecular brightness, has extended fluorescence lifetime, and displays a spontaneous blinking pattern that is promising for nanoscopy use.
红色荧光蛋白(RFPs)通常是活组织显微镜检查和全身成像的首选探针。在选择特定的RFP变体时,可能会优先考虑荧光亮度、成熟速率、单体性、激发/发射波长和低毒性,而这些特性很少能在单一蛋白质中以最佳方式组合。如果应用了诸如延长荧光寿命和/或闪烁能力等额外要求,可用的探针种类可能会大幅减少。由于传统单组分RFP的整个多样性仅属于少数几个系统发育谱系(主要是源自DsRed-、eqFP578-和eqFP611-的),因此它们的优势特性在亲缘关系较近的同源物之间出现分化也就不足为奇了。在这种情况下,针对变体特异性氨基酸残基进行系统的诱变分析,可以揭示相关RFP之间差异的起源,并有助于在新的RFP变体中整合它们的优势。例如,蛋白质FusionRed尽管由于其良好的单体性和低细胞毒性而在荧光标记方面效率较高,但与亲本mKate2相比,其荧光亮度/寿命有相当大的损失。在本论文中,我们描述了一种基于mKate2和FusionRed模板半理性设计的快速成熟单体RFP,它在分子亮度方面优于其两个亲本,具有延长的荧光寿命,并显示出一种自发闪烁模式,有望用于纳米显微镜检查。