钙离子介导的肌球蛋白热诱导凝胶形成的分子机理

Sodium-reduced meat products are in the ascendant, and recent studies have shown that calcium is a good substitute of sodium. Earlier studies of the team showed that partial replacement of sodium by calcium could change the electrostatic interaction to improve gel properties of myosin. However, mechanism of myosin gel formation mediated by calcium has not been clarified. In this project, the exposure law of functional groups, such as aromatic, aliphatic and heterocyclic amino acid side chains during heating will be systematic studied. The correlation between functional group exposure and intermolecular interaction will be analyzed, and the intermolecular interaction between molecules will be determined. The effect of calcium on the gel properties and the secondary structure of myosin during heating will be studied, and domains that protein interact with each other mediated by calcium will be identified. Finally, the major exposed functional groups, the major intermolecular interaction force, the major change of the secondary structure of myosin and the domains will be clarified. Above all, the mechanism of calcium mediated heat-induced gel formation of myosin can be clarified according to the conclusions of this project which could provide the practical guideline for sodium-reduced meat products processing.

低钠盐肉制品方兴未艾，钠盐替代研究成为热点。本团队前期研究表明钙离子部分替代钠离子能够改变体系中静电作用促进肌球蛋白热诱导凝胶形成，但机制尚不明确。本项目利用离体模型，系统研究钙离子介导的肌球蛋白解离与热聚集过程中芳香族、脂肪族和杂环族氨基酸侧链等功能基团暴露规律；研究功能基团暴露与热聚集分子间相互作用力的相关性，解析钙离子介导的肌球蛋白热聚集过程中分子间疏水相互作用、静电作用、氢键及二硫键等相互作用力变化规律；分析钙离子对肌球蛋白热诱导凝胶形成过程中凝胶特性与二级结构的影响，确证钙离子介导下肌球蛋白受热互作结构域，明确钙离子介导下促进肌球蛋白热诱导凝胶形成的主要功能基团、相互作用力、蛋白二级结构变化与互作结构域，揭示钙离子介导的肌球蛋白热诱导凝胶形成的分子机理，为低钠盐肉制品研发提供理论依据。

低钠盐肉制品符合营养健康消费需求，是新型肉制品开发的主要方向，开发新型钠盐替代物成为研究热点，Ca2+是重要的Na+替代物之一。本项目羊背最长肌肌球蛋白为试验材料，构建肌球蛋白离体模型，揭示了Ca2+影响下肌球蛋白功能基团暴露程度随温度的变化规律，明确了Ca2+影响下肌球蛋白热聚集体间的主要相互作用力，阐明了Ca2+影响下肌球蛋白构象改变与凝胶特性之间的关系，明确了Ca2+作用下肌球蛋白分子互作结构域，全面阐明了Ca2+介导的肌球蛋白热诱导凝胶形成的分子机理，为利用Ca2+替代Na+开发新型低钠盐肉制品提供理论依据。