用于连续生物传感器应用的具有改善的pH依赖性动力学的工程化单链可变片段(scFv)。

Engineered single chain variable fragments (scFvs) with improved pH-dependent kinetics for use in continuous biosensor applications.

作者信息

Wilson Ellie D, Probst David, Hamasaki Mai, Oda Miho, Kochar Varun, Xu Qianming, Tanaka Ayumi, Suzuki Hirobumi, Asano Ryutaro, Sode Koji

机构信息

Lampe Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill, North Carolina State University Chapel Hill NC 27599 USA

Department of Biotechnology and Life Science, Graduate School of Engineering, Tokyo University of Agriculture and Technology 2-24-16 Naka-cho, Koganei Tokyo 184-8588 Japan.

出版信息

RSC Adv. 2025 Jul 17;15(31):25337-25348. doi: 10.1039/d5ra02051d. eCollection 2025 Jul 15.

Abstract

One challenge in the continuous monitoring of insulin lies with the unavailability of a high-affinity biological recognition element (BRE) with kinetic parameters sufficient to track fluctuating concentrations of insulin . An approach to overcome this limitation is to engineer a high-affinity BRE to selectively modulate its binding kinetics in response to an external signal. Herein, we design and evaluate changes in the pH-dependent binding kinetics of an anti-insulin single chain variable fragment (scFv) we previously employed in a point-of-care insulin sensor. We predicted the scFv structure in complex with human insulin and selected scFv residues directly involved in insulin binding for histidine substitution. We identify one mutation, T32H, that improves the pH-sensitivity of the wild-type (WT); the of the T32H mutant is calculated to be 145.5 ± 83.1 nM at pH 7.4 and 17.4 ± 5.1 nM at pH 6.0 - an average of an 8.4× difference between the two conditions and a 3.8× increase in pH-sensitivity from the WT. We design a bio-layer interferometry (BLI) assay to interrogate the improved pH-sensitivity of the T32H mutant in tracking fluctuating insulin concentrations in dynamic pH conditions and find that improved pH-sensitivity can be leveraged to improve biosensor regeneration. These results suggest the potential for pH-sensitive antibodies to improve the development of continuous monitoring systems.

摘要

胰岛素连续监测面临的一个挑战在于,缺乏一种具有足够动力学参数以追踪胰岛素波动浓度的高亲和力生物识别元件(BRE)。克服这一限制的一种方法是设计一种高亲和力BRE,使其能够根据外部信号选择性地调节其结合动力学。在此,我们设计并评估了我们先前在即时胰岛素传感器中使用的抗胰岛素单链可变片段(scFv)的pH依赖性结合动力学变化。我们预测了与人类胰岛素结合的scFv结构,并选择直接参与胰岛素结合的scFv残基进行组氨酸取代。我们鉴定出一个突变体T32H,它提高了野生型(WT)的pH敏感性;T32H突变体在pH 7.4时的解离常数计算为145.5±83.1 nM,在pH 6.0时为17.4±5.1 nM,两种条件下平均相差8.4倍,pH敏感性比WT提高了3.8倍。我们设计了一种生物层干涉术(BLI)检测方法,以研究T32H突变体在动态pH条件下追踪波动胰岛素浓度时提高的pH敏感性,并发现提高的pH敏感性可用于改善生物传感器的再生。这些结果表明,pH敏感抗体在改善连续监测系统的开发方面具有潜力。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/0cf1/12268258/cf9b7c98cced/d5ra02051d-s1.jpg

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