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Statistical Mechanics Provides Novel Insights into Microtubule Stability and Mechanism of Shrinkage

DSpace at IIT Bombay

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Title Statistical Mechanics Provides Novel Insights into Microtubule Stability and Mechanism of Shrinkage
 
Creator JAIN, I
INAMDAR, MM
PADINHATEERI, R
 
Subject BETA-TUBULIN DIMER
DYNAMIC INSTABILITY
POLYMERIZATION DYNAMICS
CHROMOSOME MOTION
MODEL
ENDS
CAP
MORPHOGENESIS
MICROSCOPY
REVEALS
 
Description Microtubules are nano-machines that grow and shrink stochastically, making use of the coupling between chemical kinetics and mechanics of its constituent protofilaments (PFs). We investigate the stability and shrinkage of microtubules taking into account inter-protofilament interactions and bending interactions of intrinsically curved PFs. Computing the free energy as a function of PF tip position, we show that the competition between curvature energy, inter-PF interaction energy and entropy leads to a rich landscape with a series of minima that repeat over a length-scale determined by the intrinsic curvature. Computing Langevin dynamics of the tip through the landscape and accounting for depolymerization, we calculate the average unzippering and shrinkage velocities of GDP protofilaments and compare them with the experimentally known results. Our analysis predicts that the strength of the inter-PF interaction (E-m(s)) has to be comparable to the strength of the curvature energy (E-m(b)) such that E-m(s) - E-m(b) approximate to 1k(B) T, and questions the prevalent notion that unzippering results from the domination of bending energy of curved GDP PFs. Our work demonstrates how the shape of the free energy landscape is crucial in explaining the mechanism of MT shrinkage where the unzippered PFs will fluctuate in a set of partially peeled off states and subunit dissociation will reduce the length.
 
Publisher PUBLIC LIBRARY SCIENCE
 
Date 2016-01-15T10:12:15Z
2016-01-15T10:12:15Z
2015
 
Type Article
 
Identifier PLOS COMPUTATIONAL BIOLOGY, 11(2)
1553-734X
1553-7358
http://dx.doi.org/10.1371/journal.pcbi.1004099
http://dspace.library.iitb.ac.in/jspui/handle/100/18339
 
Language en