       Document 0908
 DOCN  M9440908
 TI    Folding patterns of immunoglobulin molecules identified by urea gradient
       electrophoresis.
 DT    9404
 AU    Attanasio R; Stunz GW; Kennedy RC; Department of Virology and
       Immunology, Southwest Foundation for; Biomedical Research, San Antonio,
       Texas 78228-0147.
 SO    J Biol Chem. 1994 Jan 21;269(3):1834-8. Unique Identifier : AIDSLINE
       MED/94124526
 AB    The reversible denaturant-induced unfolding of immunoglobulin molecules
       has been analyzed by transverse urea gradient gel electrophoresis and
       the effects that urea-induced unfolding exerts on the functional
       properties associated with their variable region, i.e. antigen binding
       and idiotypic expression, have been determined by Western blot analysis.
       Results obtained from these experiments indicate that urea-induced
       unfolding of the immunoglobulin molecule is a highly cooperative
       reversible process that occurs through a two-state transition with no
       accumulation of intermediates. The unfolding transition has its midpoint
       at about 6.5 M urea and appears to be slow on the time scale of
       electrophoresis. Folding intermediates in rapid equilibrium with the
       unfolded state as well as molecular forms with different electrophoretic
       mobility can be detected during refolding reactions. Results from
       Western blot analysis confirm the highly cooperative reversible
       urea-induced unfolding of immunoglobulin molecules and demonstrate that
       the unfolding transition leads to disappearance of both antigen binding
       and idiotypic expression, whereas the ability to interact with
       antibodies directed to continuous epitopes of the variable region is
       preserved. After progressive removal of the denaturing agent, the
       variable region refolds into structures that regain the functional
       properties of the native conformation.
 DE    Animal  Antibodies/*CHEMISTRY/ISOLATION & PURIF  Antibodies,
       Monoclonal/*CHEMISTRY/ISOLATION & PURIF  Antigenic Determinants/ANALYSIS
       Antigens, CD4/IMMUNOLOGY  Blotting, Western  Electrophoresis,
       Polyacrylamide Gel/METHODS  Human  HIV Antibodies/CHEMISTRY/ISOLATION &
       PURIF  IgG/*CHEMISTRY/ISOLATION & PURIF  Immunoglobulins,
       kappa-Chain/*CHEMISTRY/ISOLATION & PURIF  Kinetics  Mice  *Protein
       Folding  Rabbits  Support, U.S. Gov't, P.H.S.  Urea/*PHARMACOLOGY
       JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

