Mechanobiology Institute, National University of Singapore, Singapore, Singapore.
Department of Physics, National University of Singapore, Singapore, Singapore.
Nat Commun. 2024 May 27;15(1):4496. doi: 10.1038/s41467-024-48828-7.
Titin N2B unique sequence (N2B-us) is a 572 amino acid sequence that acts as an elastic spring to regulate muscle passive elasticity. It is thought to lack stable tertiary structures and is a force-bearing region that is regulated by mechanical stretching. In this study, the conformation of N2B-us and its interaction with four-and-a-half LIM domain protein 2 (FHL2) are investigated using AlphaFold2 predictions and single-molecule experimental validation. Surprisingly, a stable alpha/beta structural domain is predicted and confirmed in N2B-us that can be mechanically unfolded at forces of a few piconewtons. Additionally, more than twenty FHL2 LIM domain binding sites are predicted to spread throughout N2B-us. Single-molecule manipulation experiments reveals the force-dependent binding of FHL2 to the N2B-us structural domain. These findings provide insights into the mechano-sensing functions of N2B-us and its interactions with FHL2.
肌联蛋白 N2B 独特序列（N2B-us）是一段 572 个氨基酸的序列，作为弹性弹簧调节肌肉的被动弹性。它被认为缺乏稳定的三级结构，是一个由机械拉伸调节的力承载区域。在这项研究中，使用 AlphaFold2 预测和单分子实验验证研究了 N2B-us 的构象及其与四半 LIM 结构域蛋白 2（FHL2）的相互作用。令人惊讶的是，预测并证实了 N2B-us 中存在一个稳定的 α/β 结构域，该结构域可以在几皮牛顿的力下机械展开。此外，预测到超过二十个 FHL2 LIM 结构域结合位点分布在 N2B-us 中。单分子操作实验揭示了 FHL2 与 N2B-us 结构域的力依赖性结合。这些发现为 N2B-us 的机械传感功能及其与 FHL2 的相互作用提供了深入了解。
