title: Mechanical response and deformation mechanics of Type IV pili investigated using steered coarse-grained molecular dynamics simulation.
abstract: Type IV pili are long filamentous structures on the surface of bacteria, which can be rapidly assembled or disassembled with pilin subunits by molecular motors. They can generate force during retraction and are involved in many bacterial functions. Steered molecular dynamics simulations with coarse-grained MARTINI models are carried out to investigate the mechanical behaviors of pili under tension. Our study is the first to report a Young's modulus of 0.80±0.07GPa and a spring constant of 1294.6±116.5kJmol-1nm-2for pilus. Our results show the mechanical responses of pili are different from those described by the worm-like chain model and the van der Waal's interactions play a critical role in the mechanical responses. Moreover, the effects of pulling rates and virtual spring constants of pilus on Young's modulus are studied and two distinct morphological stages with the conformational changes appear during the extension of pilus are observed. This work provide insight into the mechanics and the deformation mechanism of pilus assembly.
authors.affiliation: School of Water Conservancy and Environmental Engineering, Zhengzhou University, Zhengzhou 450001, China; Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Zhao
authors.affiliation: School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.
authors.forename: Yankai
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.
authors.forename: Zhouhang
authors.initials: Z
authors.lastname: Guo
authors.affiliation: School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.
authors.forename: Yizhe
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Yongchi
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China. Electronic address: weiliu@zzu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
mesh_terms: D055119:Elastic Modulus; D010861:Fimbriae, Bacterial / Q000502:physiology*; D056004:Molecular Dynamics Simulation
keywords: Coarse-grained model; Mechanical response; Steered molecular dynamics; Type IV pilus