Document Detail


Pressure-accelerated dissociation of amyloid fibrils in wild-type hen lysozyme.
MedLine Citation:
PMID:  22225805     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The dynamics of amyloid fibrils, including their formation and dissociation, could be of vital importance in life. We studied the kinetics of dissociation of the amyloid fibrils from wild-type hen lysozyme at 25°C in vitro as a function of pressure using Trp fluorescence as a probe. Upon 100-fold dilution of 8 mg ml(-1) fibril solution in 80 mM NaCl, pH 2.2, no immediate change occurred in Trp fluorescence, but at pressures of 50-450 MPa the fluorescence intensity decreased rapidly with time (k(obs) = 0.00193 min(-1) at 0.1 MPa, 0.0348 min(-1) at 400 MPa). This phenomenon is attributable to the pressure-accelerated dissociation of amyloid fibrils into monomeric hen lysozyme. From the pressure dependence of the rates, which reaches a plateau at ~450 MPa, we determined the activation volume ΔV(0‡) = -32.9 ± 1.7 ml mol(monomer)(-1) and the activation compressibility Δκ(‡) = -0.0075 ± 0.0006 ml mol(monomer)(-1) bar(-1) for the dissociation reaction. The negative ΔV(0‡) and Δκ(‡) values are consistent with the notion that the amyloid fibril from wild-type hen lysozyme is in a high-volume and high-compressibility state, and the transition state for dissociation is coupled with a partial hydration of the fibril.
Authors:
Buddha R Shah; Akihiro Maeno; Hiroshi Matsuo; Hideki Tachibana; Kazuyuki Akasaka
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-01-03
Journal Detail:
Title:  Biophysical journal     Volume:  102     ISSN:  1542-0086     ISO Abbreviation:  Biophys. J.     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2012-01-09     Completed Date:  2012-04-18     Revised Date:  2013-06-26    
Medline Journal Info:
Nlm Unique ID:  0370626     Medline TA:  Biophys J     Country:  United States    
Other Details:
Languages:  eng     Pagination:  121-6     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Affiliation:
High Pressure Protein Research Center, Institute of Advanced Technology, Kinki University, Kinokawa, Japan.
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MeSH Terms
Descriptor/Qualifier:
Amyloid / chemistry*
Animals
Binding Sites
Computer Simulation
Enzyme Activation
Models, Chemical*
Muramidase / chemistry*
Pressure
Protein Binding
Chemical
Reg. No./Substance:
0/Amyloid; EC 3.2.1.-/hen egg lysozyme; EC 3.2.1.17/Muramidase
Comments/Corrections

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