3 research outputs found
Mechanochemical modeling of dynamic microtubule growth involving sheet-to-tube transition
Microtubule dynamics is largely influenced by nucleotide hydrolysis and the
resultant tubulin configuration changes. The GTP cap model has been proposed to
interpret the stabilizing mechanism of microtubule growth from the view of
hydrolysis effects. Besides, the microtubule growth involves the closure of a
curved sheet at its growing end. The curvature conversion also helps to
stabilize the successive growth, and the curved sheet is referred to as the
conformational cap. However, there still lacks theoretical investigation on the
mechanical-chemical coupling growth process of microtubules. In this paper, we
study the growth mechanisms of microtubules by using a coarse-grained molecular
method. Firstly, the closure process involving a sheet-to-tube transition is
simulated. The results verify the stabilizing effect of the sheet structure,
and the minimum conformational cap length that can stabilize the growth is
demonstrated to be two dimers. Then, we show that the conformational cap can
function independently of the GTP cap, signifying the pivotal role of
mechanical factors. Furthermore, based on our theoretical results, we describe
a Tetris-like growth style of microtubules: the stochastic tubulin assembly is
regulated by energy and harmonized with the seam zipping such that the sheet
keeps a practically constant length during growth.Comment: 23 pages, 7 figures. 2 supporting movies have not been uploaded due
to the file type restriction