Membrane Biology Laboratory, Transdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, 695014, India.
Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
Nat Commun. 2022 Sep 14;13(1):5377. doi: 10.1038/s41467-022-33155-6.
Tailored transmembrane alpha-helical pores with desired structural and functional versatility have promising applications in nanobiotechnology. Herein, we present a transmembrane pore DpPorA, based on the natural pore PorACj, built from D-amino acid α-helical peptides. Using single-channel current recordings, we show that DpPorA peptides self-assemble into uniform cation-selective pores in lipid membranes and exhibit properties distinct from their L-amino acid counterparts. DpPorA shows resistance to protease and acts as a functional nanopore sensor to detect cyclic sugars, polypeptides, and polymers. Fluorescence imaging reveals that DpPorA forms well-defined pores in giant unilamellar vesicles facilitating the transport of hydrophilic molecules. A second D-amino acid peptide based on the polysaccharide transporter Wza forms transient pores confirming sequence specificity in stable, functional pore formation. Finally, molecular dynamics simulations reveal the specific alpha-helical packing and surface charge conformation of the D-pores consistent with experimental observations. Our findings will aid the design of sophisticated pores for single-molecule sensing related technologies.
具有所需结构和功能多样性的定制跨膜 α-螺旋孔在纳米生物技术中有很有前途的应用。本文中，我们展示了一种基于天然孔 PorACj 的跨膜孔 DpPorA，它由 D-氨基酸 α-螺旋肽构建而成。通过单通道电流记录，我们表明 DpPorA 肽在脂质膜中自组装成均匀的阳离子选择性孔，并表现出与它们的 L-氨基酸对应物不同的性质。DpPorA 对蛋白酶具有抗性，并可作为功能性纳米孔传感器，用于检测环状糖、多肽和聚合物。荧光成像显示 DpPorA 在巨大的单层囊泡中形成了定义明确的孔，有利于亲水分子的运输。第二个基于多糖转运蛋白 Wza 的 D-氨基酸肽形成了瞬时孔，证实了稳定、功能性孔形成中的序列特异性。最后，分子动力学模拟揭示了 D-孔的特定α-螺旋堆积和表面电荷构象，与实验观察结果一致。我们的研究结果将有助于设计用于单分子传感相关技术的复杂孔。
