The effect of water activity on the association constant and the enthalpy of reaction between lysozyme and the specific antibodies D1.3 and D44.1.

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TitleThe effect of water activity on the association constant and the enthalpy of reaction between lysozyme and the specific antibodies D1.3 and D44.1.
Publication TypeJournal Article
Year of Publication1996
AuthorsGoldbaum, FA, Schwarz, FP, Eisenstein, E, Cauerhff, A, Mariuzza, RA, Poljak, RJ
JournalJ Mol Recognit
Volume9
Issue1
Pagination6-12
Date Published1996 Jan-Feb
ISSN0952-3499
KeywordsAlcohols, Antibodies, Monoclonal, Antigen-Antibody Reactions, Binding Sites, Antibody, Calorimetry, Glycerol, Immunoglobulin Fragments, Immunoglobulin Variable Region, Molecular Conformation, Muramidase, Thermodynamics, Ultracentrifugation, Water
Abstract

The reactions of lysozyme with the specific monoclonal antibody D1.3, its Fv fragment and a mutant of the Fv, were studied under conditions of reduced water activity through the addition of the cosolutes glycerol, ethanol, dioxane and methanol. Titration calorimetry, BIAcoreTM and ultracentrifugal analyses were used to determine enthalpy of reactions and affinity constants. There was a decrease in the values of the enthalpies of reactions as well as in the association constants which was proportional to the decrease in water activity. These results are consistent with a structural model in which water molecules bound to the antigen and the antibody are conserved upon complex formation and provide bonds which are important for the stability of the complex. In contrast, the reaction of lysozyme with the specific monoclonal antibody D44.1, or its Fab, showed the inverse effect: a small increase in the value of the association constant with decreasing water molarities. This is in agreement with a model in which binding of antigen to antibody D44.1 is accompanied by the release of a very small number of water molecules.

DOI10.1002/(SICI)1099-1352(199601)9:1<6::AID-JMR240>3.0.CO;2-V
Alternate JournalJ. Mol. Recognit.
PubMed ID8723314
Grant ListGM52801 / GM / NIGMS NIH HHS / United States
RR08937 / RR / NCRR NIH HHS / United States