Document Detail

A (1)H-NMR study on the effect of high pressures on beta-lactoglobulin.
MedLine Citation:
PMID:  10995289     Owner:  NLM     Status:  MEDLINE    
1H NMR was used to study the effect of high pressure on changes in the structure of beta-lactoglobulin (beta-Lg), particularly the strongly bonded regions, the "core". beta-Lg was exposed to pressures ranging from 100 to 400 MPa at neutral pH. After depressurization and acidification to pH 2.0, (1)H NMR spectra were taken. Pressure-induced unfolding was studied by deuterium exchange. Refolding was also evaluated. Our results showed that the core was unaltered at 100 MPa but increased its conformational flexibility at >/=200 MPa. Even though the core was highly flexible at 400 MPa, its structure was found to be identical to the native structure after equilibration back to atmospheric pressure. It is suggested that pressure-induced aggregates are formed by beta-Lg molecules maintaining most of their structure, and the intermolecular -SS- bonds, formed by -SH/-SS- exchange reaction, are likely to involve C(66)-C(160) rather than C(106)-C(119). In addition, the beta-Lg variants A and B could be distinguished in a (1)H NMR spectrum from a solution made with the AB mixed variant, by the differences in chemical shifts of M(107) and C(106); structural implications are discussed. Under pressure, the core of beta-Lg A seemed to unfold faster than that of beta-LgB. The structural recovery of the core was full for both variants.
J Belloque; R López-Fandiño; G M Smith
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  48     ISSN:  0021-8561     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2000 Sep 
Date Detail:
Created Date:  2000-11-13     Completed Date:  2000-11-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  3906-12     Citation Subset:  IM    
Instituto de Fermentaciones Industriales (C.S.I.C.), Juan De La Cierva, 3, 28006 Madrid, Spain.
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MeSH Terms
Lactoglobulins / chemistry*
Magnetic Resonance Spectroscopy
Protein Denaturation
Protein Folding
Reg. No./Substance:
0/Lactoglobulins; 0/Protons

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