Abstract
Monoclonal anti-DNA autoantibody BV 04-01 catalyzed hydrolysis of DNA in the presence of Mg2+. Catalysis was associated with BV 04-01 IgG, Fab, and single-chain-antibody (SCA) proteins. Cleavage of both ss and dsDNA was observed with efficient hydrolysis of the C-rich region of A7C7ATATAGCGCGT2, as well as a preference for cleaving within CG-rich regions of dsDNA. Data on specificity of ssDNA hydrolysis and kinetic data obtained from wild-type SCA, and two SCA mutants were used to model the catalytically active antibody site using the previously resolved X-ray structure of BV 04-01. The resulting model suggested that the target phosphodiester bond is activated by induction of conformational strain. In addition, the antibody-DNA complex contained a Mg2+ coordination site composed of the L32Tyr and L27dHis side chains and a DNA 3'-phosphodiester group. Induction of strain along with the metal coordination could be part of the mechanism by which this antibody catalyzes DNA hydrolysis. Sequence data for BV 04-01 V(H) and V(L) genes suggested that the proposed catalytic- antibody active site was germline-encoded. This observation suggests that catalytic activity might represent an important - rarely examined - function for some antibody molecules.
Original language | English (US) |
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Pages (from-to) | 95-105 |
Number of pages | 11 |
Journal | Applied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology |
Volume | 83 |
Issue number | 1-3 |
DOIs | |
State | Published - 2000 |
Keywords
- Abzyme
- Autoantibody
- Catalysis