Schlatterer Rebecca, Marczynski Matthias, Hermann Bianca, Lieleg Oliver, Balzer Bizan N
Department of Chemistry and Pharmacy, Institute of Physical Chemistry, University of Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
Department of Materials Engineering, School of Engineering and Design, Technical University of Munich, Boltzmannstr. 15, 85748 Garching, Germany.
Nano Lett. 2025 Feb 5;25(5):1765-1774. doi: 10.1021/acs.nanolett.4c03088. Epub 2025 Jan 22.
Mucins are the macromolecular key components of mucus. On wet epithelia of mammals, mucin solutions and gels act as powerful biolubricants and reduce friction and wear by generating a sacrificial layer and establishing hydration lubrication. Yet the structure-function relationship of mucin adhesion and lubrication remains elusive. We study the adhesion behavior of mucin using atomic force microscopy-based single molecule force spectroscopy with covalently attached, lab-purified salivary MUC5B and gastric MUC5AC. We can resolve the structural motifs mediating adhesion on chemically distinct substrates, such as highly oriented pyrolytic graphite and steel. We report on force-induced partial unfolding of the von Willebrand factor type D like domains and deliver their unfolding rates and free energy barriers. These domains serve to dissipate energy during the desorption process of mucins. Partial mucin unfolding might significantly contribute to the stability of a sacrificial mucin layer during shearing processes, enhancing the lubrication potential of mucin solutions.
黏蛋白是黏液的大分子关键成分。在哺乳动物的湿润上皮组织上，黏蛋白溶液和凝胶充当强大的生物润滑剂，通过形成牺牲层和建立水合润滑来减少摩擦和磨损。然而，黏蛋白黏附与润滑的结构-功能关系仍然难以捉摸。我们使用基于原子力显微镜的单分子力谱，结合共价连接的、实验室纯化的唾液MUC5B和胃MUC5AC，研究黏蛋白的黏附行为。我们能够解析在化学性质不同的底物上介导黏附的结构基序，如高度取向的热解石墨和钢。我们报告了类血管性血友病因子D结构域的力诱导部分解折叠情况，并给出了它们的解折叠速率和自由能垒。这些结构域在黏蛋白的解吸附过程中起到耗散能量的作用。黏蛋白的部分解折叠可能在剪切过程中对牺牲性黏蛋白层的稳定性有显著贡献，增强黏蛋白溶液的润滑潜力。
