圆柱壳层中自驱动微丝超簇形成  

Super-cluster formation of self-propelling microfilaments in a cylindrical shell

作　　者：沈晨 许天亮 唐然[3] 田文得 陈康 Chen Shen;Tian-Liang Xu;Ran Tang;Wen-De Tian;Kang Chen(Center for Soft Condensed Matter Physics&Interdisciplinary Research,School of Physical Science and Technology,Soochow University,Suzhou 215006,China;Kunshan No.1 High School,Kunshan 215300,China;Children’s Hospital of Soochow University,Suzhou 215006,China)

机构地区：[1]苏州大学物理科学与技术学院,软凝聚态物理及交叉研究中心,苏州215006 [2]昆山市第一中学,昆山215300 [3]苏州大学附属儿童医院,苏州215006

出　　处：《科学通报》2023年第27期3691-3697,共7页Chinese Science Bulletin

基　　金：国家自然科学基金(21674078,21774091,21574096);江苏省重点实验室开放基金(KJS2225)资助。

摘　　要：生命物质一般通过能量消耗过程自组装成功能结构,组装过程往往在受限环境中发生.理解受限状态下活性链结构和动力学对理解生命系统的行为具有重要意义.本文采用朗之万动力学模拟,研究了自驱动微丝在圆柱壳层内的结构和动力学,发现微丝呈现两态:熔态和超簇态.超簇态的形成依赖于微丝的面积分数、自驱动力大小和微丝刚度.适当的刚性和自驱动力是超簇形成的必要条件,体积排斥效应和自驱动力产生的有效吸引作用是超簇形成的物理机制.超簇形成后在壳层内可能呈现沿圆柱轴向的匀速平动和垂直于轴向的匀速转动.在固定微丝面积分数的条件下,半柔性微丝随着自驱动力的增加呈现熔态的重入现象;固定驱动力大小而改变刚性大小,同样会导致熔态的重入,表明链的刚性过大或过小都不利于超簇的形成.Living matter often self-organizes into functional structures through active,energy-consuming processes.Biopolymers such as microfilaments and microtubules exhibit very interesting self-organization phenomena in cells.For example,microfilaments at a high density display loops and vortices as they slide over motor-coated air-buffered interfaces due to inelastic collisions.Molecular motors,a kind of bio-enzymes,import active effects to biopolymers and give rise to the movement of these polymers.Bio-enzymes have been considered to be nanomachines due to their ability to remodel the structure and dynamics of biopolymers.For instance,Condensin plays a central role in chromosome assembly and segregation during mitosis and meiosis via regulating the number and distribution of DNA breaks and crossovers.When biopolymers with activity are gathered together,completely different behaviors,such as dynamic patterns and abnormal rheological properties,from those in thermal equilibrium systems can be observed.In addition to the rich physical phenomena arising from the self-organization of active polymers,understanding how these structures arise from the underlying dynamics will help elucidate their functions.Theoretically,the collective behavior of these active polymers has been intensively studied.Activity was often introduced as colored noise acting tangentially on an individual filament.With the activity,a single filament shows a net longitudinal drift.In the two dimensions,the combination of excluded-volume interactions and activity results in several distinct dynamics phases as a function of bending rigidity,activity,and length of filaments.Boundaries are ubiquitous in living systems,which impose confinement effects on the biopolymers.Many important biological processes take place in a closed environment,such as the packaging of DNA or RNA in eukaryotic cells.It has been found that semi-flexible polymer chains without activity confined in spheres can form localized helical structures.In fact,the shape of the confined space

关 键 词：活性物质 超簇结构 刚性 活性力 

分 类 号：Q61[生物学—生物物理学]