Turner, Matthew S. , Agarwal, G., Jones, C. W., Wang, J. C., Kwong, S., Ferrone, F. A., Josephs, R. and Briehl, R. W. (2006) Fiber depolymerization. Biophysical Journal, Vol.91 (No.3). pp. 1008-1013. doi:10.1529/biophysj.105.075333 ISSN 0006-3495.

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Abstract

Depolymerization is, by definition, a crucial process in the reversible assembly of various biopolymers. It may also be an important factor in the pathology of sickle cell disease. If sickle hemoglobin fibers fail to depolymerize fully during passage through the lungs then they will reintroduce aggregates into the systemic circulation and eliminate or shorten the protective delay (nucleation) time for the subsequent growth of fibers. We study how depolymerization depends on the rates of end- and side-depolymerization, kend and kside, which are, respectively, the rates at which fiber length is lost at each end and the rate at which new breaks appear per unit fiber length. We present both an analytic mean field theory and supporting simulations showing that the characteristic fiber depolymerization time View the MathML source depends on both rates, but not on the fiber length L, in a large intermediate regime 1 much less-than ksideL2/kend much less-than (L/d)2, with d the fiber diameter. We present new experimental data which confirms that both mechanisms are important and shows how the rate of side depolymerization depends strongly on the concentration of CO, acting as a proxy for oxygen. Our theory remains rather general and could be applied to the depolymerization of an entire class of linear aggregates, not just sickle hemoglobin fibers.

Item Type:	Journal Article
Subjects:	Q Science > QH Natural history > QH301 Biology
Divisions:	Faculty of Science, Engineering and Medicine > Science > Physics
Library of Congress Subject Headings (LCSH):	Biopolymers -- Separation, Nucleation, Polymerization, Carbon dioxide -- Physiological effect
Journal or Publication Title:	Biophysical Journal
Publisher:	Biophysical Society
ISSN:	0006-3495
Official Date:	August 2006
Dates:	Date Event August 2006 Published
Volume:	Vol.91
Number:	No.3
Page Range:	pp. 1008-1013
DOI:	10.1529/biophysj.105.075333
Status:	Peer Reviewed
Access rights to Published version:	Open Access (Creative Commons)
Funder:	National Heart, Lung, and Blood Institute
Grant number:	HL58512 (NHLBI), HL22654 (NHLBI)

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