State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
Wuxi Biologics Co., Ltd, Wuxi 214092, China.
Food Chem. 2024 Feb 1;433:137385. doi: 10.1016/j.foodchem.2023.137385. Epub 2023 Sep 9.
Enzymatic deamidation is a promising approach in enhancing the solubility of myofibrillar proteins (MPs) in water paving the way of tailor manufacturing muscle protein-based beverages. This work aimed to clarify the solubilization mechanism by deciphering myosin thick filaments assembly as affected by protein-glutaminase deamidation. With the extension of deamidation, filamentous structures in MPs shortened continuously. Dynamic monitoring of quartz crystal microbalance-dissipated showed the adsorption capacity of the deaminated MPs was reduced from 3.66 ng/cm to 2.03 ng/cm, indicating that the ability to assemble myosin thick filaments was significantly weakened. By simulating the surface charge, it was found that deamidation may neutralize the positive charged clusters distanced at 14-29 nm from rod C-terminus. Since this region confers myosin electrostatic property to initiate staggered dimerization, deamidation in this region, which severely affected the electrostatic balance between residues, impaired ordered thick filament growing and elongating, thus promoting the solubilization of MPs in water.
酶法脱酰胺是一种提高肌球蛋白（MPs）在水中溶解度的有前途的方法，为定制生产肌肉蛋白基饮料铺平了道路。本研究旨在通过解析肌球蛋白重链脱酰胺对肌球蛋白粗丝组装的影响来阐明其溶解机制。随着脱酰胺的延长，MPs 的丝状结构不断缩短。石英晶体微天平耗散的动态监测表明，脱氨基 MPs 的吸附能力从 3.66ng/cm 降低到 2.03ng/cm，表明组装肌球蛋白粗丝的能力显著减弱。通过模拟表面电荷，发现脱酰胺可能使距离杆 C 末端 14-29nm 的正电荷簇中和。由于该区域赋予肌球蛋白静电特性以启动交错二聚化，因此该区域的脱酰胺会严重影响残基之间的静电平衡，破坏有序的粗丝生长和伸长，从而促进 MPs 在水中的溶解。
