Document Detail


Structure and dynamics of human vimentin intermediate filament dimer and tetramer in explicit and implicit solvent models.
MedLine Citation:
PMID:  20358386     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Intermediate filaments, in addition to microtubules and microfilaments, are one of the three major components of the cytoskeleton in eukaryotic cells, and play an important role in mechanotransduction as well as in providing mechanical stability to cells at large stretch. The molecular structures, mechanical and dynamical properties of the intermediate filament basic building blocks, the dimer and the tetramer, however, have remained elusive due to persistent experimental challenges owing to the large size and fibrillar geometry of this protein. We have recently reported an atomistic-level model of the human vimentin dimer and tetramer, obtained through a bottom-up approach based on structural optimization via molecular simulation based on an implicit solvent model (Qin et al. in PLoS ONE 2009 4(10):e7294, 9). Here we present extensive simulations and structural analyses of the model based on ultra large-scale atomistic-level simulations in an explicit solvent model, with system sizes exceeding 500,000 atoms and simulations carried out at 20 ns time-scales. We report a detailed comparison of the structural and dynamical behavior of this large biomolecular model with implicit and explicit solvent models. Our simulations confirm the stability of the molecular model and provide insight into the dynamical properties of the dimer and tetramer. Specifically, our simulations reveal a heterogeneous distribution of the bending stiffness along the molecular axis with the formation of rather soft and highly flexible hinge-like regions defined by non-alpha-helical linker domains. We report a comparison of Ramachandran maps and the solvent accessible surface area between implicit and explicit solvent models, and compute the persistence length of the dimer and tetramer structure of vimentin intermediate filaments for various subdomains of the protein. Our simulations provide detailed insight into the dynamical properties of the vimentin dimer and tetramer intermediate filament building blocks, which may guide the development of novel coarse-grained models of intermediate filaments, and could also help in understanding assembly mechanisms.
Authors:
Zhao Qin; Markus J Buehler
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-04-01
Journal Detail:
Title:  Journal of molecular modeling     Volume:  17     ISSN:  0948-5023     ISO Abbreviation:  J Mol Model     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2011-01-03     Completed Date:  2011-12-19     Revised Date:  2013-03-15    
Medline Journal Info:
Nlm Unique ID:  9806569     Medline TA:  J Mol Model     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  37-48     Citation Subset:  IM    
Affiliation:
Center for Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA, USA.
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MeSH Terms
Descriptor/Qualifier:
Humans
Models, Molecular*
Polymers
Protein Structure, Tertiary
Solvents / chemistry
Vimentin / chemistry*
Chemical
Reg. No./Substance:
0/Polymers; 0/Solvents; 0/Vimentin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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