近日，德国马克斯·普朗克分子细胞生物学和遗传学研究所Brugus, Jan团队提出了一种测量多组分生物分子凝聚物组成的无标记方法。相关论文发表在2025年9月3日出版的《自然-化学》杂志上。

许多亚细胞区室是由多种组分组成的生物分子凝聚体，通常包括几种不同的蛋白质和核酸。然而，目前用于测量冷凝物组成的工具是有限的，并且不能定量地捕获这种复杂性，因为它们要么需要荧光标记，这可能会干扰组成，要么只能区分一种或两种成分。

研究组描述了一种基于定量相位成像和结合线和折射率分析的无标记方法，用于测量多组分重构凝析油的成分。他们首先在二元混合物中验证了该方法，揭示了序列编码的密度变化和由全长蛋白质组成的凝聚体的复杂老化动力学。然后，该研究团队进行了绑线和折射率分析，以同时解析含RNA和多种RNA结合蛋白构建物的多组分凝聚物中五种大分子溶质的浓度。他们的测量结果揭示了密度和组成的意想不到的解耦，强调了在多组分凝聚物中确定分子化学计量的必要性。该研究团队预见这种方法能够研究凝析物性质和功能的组成规律。

附：英文原文

Title: A label-free method for measuring the composition of multicomponent biomolecular condensates

Author: McCall, Patrick M., Kim, Kyoohyun, Shevchenko, Anna, Ruer-Gru, Martine, Peychl, Jan, Guck, Jochen, Shevchenko, Andrej, Hyman, Anthony A., Brugus, Jan

Issue&Volume: 2025-09-03

Abstract: Many subcellular compartments are biomolecular condensates made of multiple components, often including several distinct proteins and nucleic acids. However, current tools to measure condensate composition are limited and cannot capture this complexity quantitatively because they either require fluorescent labels, which can perturb composition, or can distinguish only one or two components. Here we describe a label-free method based on quantitative phase imaging and analysis of tie-lines and refractive index to measure the composition of reconstituted condensates with multiple components. We first validate the method empirically in binary mixtures, revealing sequence-encoded density variation and complex ageing dynamics for condensates composed of full-length proteins. We then use analysis of tie-lines and refractive index to simultaneously resolve the concentrations of five macromolecular solutes in multicomponent condensates containing RNA and constructs of multiple RNA-binding proteins. Our measurements reveal an unexpected decoupling of density and composition, highlighting the need to determine molecular stoichiometry in multicomponent condensates. We foresee this approach enabling the study of compositional regulation of condensate properties and function.

DOI: 10.1038/s41557-025-01928-3

Source: https://www.nature.com/articles/s41557-025-01928-3