Document Detail


Absence of large-scale conformational change upon limited proteolysis of ovalbumin, the prototypic serpin.
MedLine Citation:
PMID:  2645277     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1H and 31P NMR spectroscopies have been used to examine the effects of limited proteolysis with subtilisin Carlsberg on the global conformation of ovalbumin and on the local environment of phosphoserine 344, a residue two positions removed from the site of proteolysis. Such limited proteolysis has been shown to result in excision of a hexapeptide from the region of the protein that, in other serine protease inhibitors (serpins), contains the reactive center. Based on the structure of the related serpin alpha 1-antitrypsin, it has been predicted that phosphoserine 344 should undergo a large change in environment upon proteolysis of ovalbumin (Löbermann, H., Tokuoka, R., Deisenhofer, J., and Huber, R. (1984) J. Mol. Biol. 177, 531-550). Proteolysis of ovalbumin produces a small upfield shift (0.15 ppm) of the 31P resonance of phosphoserine 344. In addition, the pKa of phosphoserine 344 is raised by 0.1 pH unit. At pH 8.5, phosphoserine 344 in cleaved ovalbumin (plakalbumin) is as accessible to hydrolysis by Escherichia coli alkaline phosphatase as it is in native ovalbumin. 1H NMR shows that dephosphorylation of serine 344 has an imperceptible effect on the protein's conformation. Similarly, little effect on conformation is seen by 1H NMR upon proteolysis of ovalbumin. These findings suggest that ovalbumin does not undergo a marked conformational change analogous to that inferred for the related members of the serpin superfamily, alpha 1-antitrypsin and antithrombin III, nor do the residues close to the site of proteolysis appear to change environment from that of an exposed loop to a buried strand of beta-sheet. These findings are not consistent with the hypothesis of Carrell and Owen ((1985) Nature 317, 730-732) for the role of the exposed loop in serpins of directly facilitating conformational change upon cleavage of the loop. Instead, it is proposed that cleavage of the exposed loop alters the solvent accessibility of residues formerly covered by the loop and that this provides the thermodynamic impetus for conformational change, perhaps by disruption of a salt bridge crucial to the integrity of the native structure.
Authors:
P Gettins
Related Documents :
7118427 - Biofunctional evaluation of a hydrogen bond stabilizing the conformation in the cyclic ...
4463967 - Analysis of the code relating sequence to conformation in globular proteins. an informa...
10333177 - Nmr structures of a nonapeptide from dna binding domain of human polymerase-alpha deter...
25463057 - Host-defense peptides from skin secretions of fraser's clawed frog xenopus fraseri (pip...
15775967 - Global conformational rearrangements during the activation of the gdp/gtp exchange fact...
2478527 - Purification and structural analysis of a latent form of transforming growth factor-bet...
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  264     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1989 Mar 
Date Detail:
Created Date:  1989-04-03     Completed Date:  1989-04-03     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  3781-5     Citation Subset:  IM    
Affiliation:
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Chickens
Hydrogen-Ion Concentration
Magnetic Resonance Spectroscopy
Ovalbumin / ultrastructure*
Phosphoserine
Protease Inhibitors*
Protein Conformation
Structure-Activity Relationship
Subtilisins / pharmacology
Grant Support
ID/Acronym/Agency:
HL32595/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Protease Inhibitors; 17885-08-4/Phosphoserine; 9006-59-1/Ovalbumin; EC 3.4.21.-/Subtilisins

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


Previous Document:  Mutational analysis of the mitochondrial Rieske iron-sulfur protein of Saccharomyces cerevisiae. I. ...
Next Document:  In vitro use of monoclonal antibodies in Escherichia coli S-30 extracts to determine the RNA polymer...