弹性蛋白力学特性的单分子力谱  

Mechanical properties of elastomeric proteins studied by single molecule force spectroscopy

作　　者：周浩天 高翔[1] 郑鹏[2] 秦猛[1] 曹毅[1] 王炜[1] 

机构地区：[1]南京大学物理学院,南京210093 [2]南京大学化学化工学院,南京210023

出　　处：《物理学报》2016年第18期144-161,共18页Acta Physica Sinica

基　　金：江苏省六大人才高峰支持计划和国家自然科学基金(批准号:21522402;11374148;11334004;81121062)资助的课题~~

摘　　要：弹性蛋白是一类有着特殊力学特性的蛋白.在生物体内它们是承受和传递力的主要媒介;在生物体外,它们更是被广泛地用作高强度的生物材料.根据其功能不同,弹性蛋白的力学特性也各异.有些具有比较高的力学强度,有些则具有较大的延展性和弹性.科学家们很早就采用多种手段来人工合成弹性蛋白用于材料和纳米领域,但对于弹性蛋白的力学特性和序列结构之间的关系还不甚明晰.本综述介绍通过单分子力谱的实验方法来直接表征单根蛋白质在受力下结构的变化,研究其力学特性.基于Bell模型,推导出了蛋白质解折所需力与拉伸速率之间的关系,揭示了蛋白质力学强度的动力学特性,当拉伸速率较低时,解折叠力将正比于拉伸速率,对于较大的拉伸速率,解折叠力与拉伸速率成指数关系;探讨了决定蛋白质力学特性的结构因素和调控蛋白质力学特性的实验方法;介绍了单分子力谱测量的实验方法,包括基于光镊、磁镊和原子力显微镜的单分子力谱技术,着重介绍了原子力显微镜单分子力谱,并特别介绍了多聚蛋白技术来提供单分子测量的"指纹谱"和提高测量效率;论述了基于原子力显微镜单分子力谱研究蛋白质力学特性的最新进展,包括提高原子力显微镜的稳定性和力分辨率的方法,与荧光标记法相结合来提高实验效率的技术和高速扫描原子力显微镜;阐述了如何通过单分子力谱实验来理性设计蛋白质材料的力学特性,并对未来的研究热点做了展望.Elastomeric proteins are a special class of proteins with unique mechanical functions.They bear,transduce mechanical forces inside cell,and serve as biomaterials of high elasticities and strengths outside cell.Depending on their functions,the mechanical properties of elastomeric proteins are very diverse.Some of them are of high mechanical stability and the others are of high extensibility and toughness.Although many elastomeric proteins are engineered for the applications in the fields of biomaterials and nanotechnology,the molecular determinant of the mechanical stability remains elusive.In this review,we summarize recent advances in the field of protein mechanics studied by using single molecule force spectroscopy.Force spectroscopy enables people to probe the unfolding properties of protein domains,thus paving the way for building special proteins with characteristic mechanical functions.To begin with,it is necessary to clarify the factors and their relations with the unfolding force,which is deduced based on Bell＇s expression.It turns out that the unfolding force is proportional to pulling speed when the speed is relatively small,and has a logarithmic relation in the high-speed approximation.After the external determinant of the force probe is clarified,some intrinsic factors are to be discussed.Hydrogen bound and electrostatic force,rather than covalent bond,contribute to the mechanical performances of proteins.Those interactions rely on the topology structures of protein molecules.By changing the structures of proteins,researchers now manage to change the mechanical characteristics of certain proteins.Since single protein is unable to be detected by traditional optic microscope,three devices used to observe and manipulate single protein are introduced in the present paper.These include atomic force microscopy,magnetic tweezers and optical tweezers.Among them,a more detailed explanation of atomic force microscope（AFM） is provided,which briefly describes the basic mechanism and structure of AFM and pos

关 键 词：单分子力谱 原子力显微镜 多聚蛋白 蛋白质材料 

分 类 号：Q51[生物学—生物化学]