Evonogenin

Conclusions The structure of a new cardiac aglycone, evonogenin, isolated from the seeds ofEvonymus europaea auct. has been established. Evonogenin is 1, 3, 5, 14-tetrahydroxycard-20(22)-enolide.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 5, pp. 386–389, 1969     

DNA hydrolysis by monoclonal autoantibody BV 04-01

Monoclonal anti-DNA autoantibody BV 04-01 catalyzed hydrolysis of DNA in the presence of Mg²⁺. Catalysis was asssociated 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 nn 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 L27d His 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.