DNA hydrolysis by monoclonal anti-ssDNA autoantibody BV 04-01: Origins of catalytic activity

Autor: L. Scott Rodkey, Jon N. Rumbley, Alexander G. Gabibov, Oksana I. Makarevich, Dmitry V. Schourov, Gennady V. Gololobov, Catherine A. Rumbley, Edward W. Voss
Rok vydání: 1997
Předmět:
Zdroj: Molecular Immunology. 34:1083-1093
ISSN: 0161-5890
DOI: 10.1016/s0161-5890(97)00129-6
Popis: Monoclonal anti-DNA autoantibody BV 04-01 catalyzed hydrolysis of DNA in the presence of Mg 2+ ions. DNA hydrolyzing activity was associated with BV 04-01 IgG, Fab, and SCA 04-01 proteins. Pronounced cleavage specificity for both ss and dsDNA was observed with efficient hydrolysis of the C-rich region of the oligonucleotide A 7 C 7 ATATAGCGCGT 7 as well as preference for cleavage within CG-rich regions of double-stranded DNA. Data on specificity of ssDNA hydrolysis and kinetic data obtained from wild-type SCA 04-01 and two SCA 04-01 mutants (L32Phe and L27dHis) were used to model the catalytically active antibody site utilizing the previously resolved X-ray structure of (dT) 3 liganded Fab 04-01. The resulting model suggested that BV 04-01 activates the target phosphodiester bond by induction of conformational strain. In addition, the antibody-DNA complex contained a potential Mg 2+ ion coordination site composed of the L32Tyr and L27dHis amino acid side chains and a DNA 3′-phosphodiester group. Induction of strain and metal coordination could be constituents of a mechanism by which this antibody catalyzed DNA hydrolysis. Sequence data for BV 04-01 V H and V L genes suggested that the proposed catalytic antibody active site was germ-line encoded. This observation suggests the hypothesis that catalytic activity might represent an important but unspecified function of some antibody molecules.
Databáze: OpenAIRE