Depletion force from macromolecular crowding enhances mechanical stability of protein molecules

Depletion force from macromolecular crowding enhances mechanical stability of protein molecules
Engineering Village 2
2006 Elsevier Inc.
Accession number: 8955161

Title: Depletion force from macromolecular crowding enhances mechanical stability of protein molecules

Authors: Jian-Min Yuan1 ; Guanghui Ping1 ; Guoliang Yang1

Author affiliation: 1 Dept. of Phys., Drexel Univ., Philadelphia, PA, USA

Serial title: Polymer

Abbreviated serial title: Polymer (UK)

Volume: 47

Issue: 7

Publication date: 22 March 2006

Pages: 2564-70

Language: English

ISSN: 0032-3861


Document type: Journal article (JA)

Publisher: Elsevier

Country of publication: UK

Material Identity Number: P166-2006-006

Abstract: In crowded solutions the presence of many cosolutes often affects the stability of compact polymers, such as globular proteins. Important examples of crowded environments are those inside some cells, where protein stability or aggregation rates are affected by the presence of co-existing bio-macromolecules. In the present article the concept of depletion force from colloidal physics and theoretical techniques developed for polymer science have been applied to study the effects of macromolecular crowding on protein stability. A continuous three-dimensional polymer model is used to simulate the behavior of protein under the conditions of macromolecular crowding and the depletion force based on such a model is calculated. Calculated results have been compared with the measured results in our laboratory, where the enhancement of the forces required to unfold ubiquitin molecules in a solution crowded with dextran has been measured using single-molecule atomic force microscopy techniques. Comparison between the calculated results and experimental observations shows that only qualitative agreement has been reached in the sense that both show a larger force required because of crowding as a protein molecule is mechanical stretched, but the magnitude of the enhancement of the unfolding force theoretically predicted is small compared to the measured value. Possible sources of discrepancy and improvements of the model are discussed. [All rights reserved Elsevier]

Number of references: 39

Inspec controlled terms: atomic force microscopy - biochemistry - biomechanics - colloids - mechanical stability - molecular biophysics - physiological models - polymers - proteins

Uncontrolled terms: depletion force - macromolecular crowding - mechanical stability - protein molecules - compact polymers - globular proteins - colloidal physics - continuous three-dimensional polymer model - ubiquitin molecule unfolding - dextran - single-molecule atomic force microscopy - mechanical stretching

Inspec classification codes: A8745 Biomechanics, biorheology, biological fluid dynamics - A8715P Model reactions in molecular biophysics - A8710 General, theoretical, and mathematical biophysics - A8270D Colloids

Treatment: Theoretical or Mathematical (THR)

Discipline: Physics (A)

DOI: 10.1016/j.polymer.2005.12.085

Database: Inspec

Copyright 2006, The Institution of Engineering and Technology
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