Document Detail


Local compressibilities in insulin as determined from pressure tuning hole burning experiments and MD simulations.
MedLine Citation:
PMID:  19791416     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We present a hole burning study on insulin in a glycerol-water solvent by using the intrinsic amino acid tyrosine as a photochemical probe. The focus of the experiments is on the comparative pressure response of the spectral holes for insulin in its native state, in its chemically denatured state and for tyrosine in the glycerol-water solvent. From an analysis of the color effect of the pressure response, we can identify two different spectral ranges characterized by a markedly different sensitivity to pressure. We conclude that at least two tyrosines (or two groups of tyrosines) out of the eight in the insulin dimer are photochemically labeled, and that they are characterized by markedly different compressibilities, namely 0.08 and 0.13 GPa(-1), respectively. An interesting observation concerns the compressibility in the unfolded state: It is significantly lower and closer to the value measured for the pure tyrosine molecule in a glycerol-water solvent. In contrast to the native state, the response of the various tyrosines in the unfolded state to pressure variations is quite uniform. The experiments are compared with MD simulations of monomeric insulin at ambient temperature. The computational results show that the local compressibilities around the different tyrosines vary significantly and that they strongly depend on whether just the first shell of molecules or the first two shells are included in the local volume.
Authors:
Christoph Schnell; Maria Reif; Christina Scharnagl; Josef Friedrich
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Physical chemistry chemical physics : PCCP     Volume:  7     ISSN:  1463-9076     ISO Abbreviation:  Phys Chem Chem Phys     Publication Date:  2005 May 
Date Detail:
Created Date:  2009-10-01     Completed Date:  2009-10-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100888160     Medline TA:  Phys Chem Chem Phys     Country:  England    
Other Details:
Languages:  eng     Pagination:  2217-24     Citation Subset:  IM    
Affiliation:
Physik-Department E14 and Lehrstuhl für Physik Weihenstephan, Technische Universität München, D-85350 Freising, Germany.
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MeSH Terms
Descriptor/Qualifier:
Computer Simulation
Glycerol
Insulin / chemistry*
Models, Molecular
Protein Conformation
Protein Denaturation
Solvents
Tyrosine / chemistry
Water
Chemical
Reg. No./Substance:
0/Solvents; 0/insulin dimers; 11061-68-0/Insulin; 55520-40-6/Tyrosine; 56-81-5/Glycerol; 7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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