Specificity and kinetics defining the interaction between a murine monoclonal autoantibody and DNA.

摘要: Interactions between a murine monoclonal anti-DNA autoantibody (BV17-45) and DNA were examined by direct binding competitive radioimmunoassays. Binding isotherms constructed titration of purified BV17-45 with series distinct 32P-labeled double-stranded ([32P]dsDNA) fragments super-impossible, suggesting: 1) BV17-45/[32P]dsDNA is independent dsDNA size using greater than or equal to 192 base pairs in length, 2) does not exhibit stringent sequence specificity. Single-stranded DNA-specific antibody BV04-01 did react [32P]dsDNA, confirming its duplex character. In competition experiments, cross-reacted phage (phi X174, M13) RF AND VIRION DNAS AT PICOMOLAR concentrations. Selectivity for B-form was suggested the ability poly(dA) . poly(dT), but other helical forms, block BV17-45/[32P] binding. Among four deoxyribohomopolymers, only deoxyadenylic acid polymers completely inhibited complex formation. [32P]dsDNA relatively insensitive ionic strength, suggesting minimal contribution electrostatic forces free energy. Measured association dissociation rate constants (4 degrees C) 7.4 X 10(6) M-1 s-1 9.2 10(-5) s-1, respectively, yielding functional affinity 8 10(10) M-1. Results are discussed terms relative B-DNA structural substructural determinants mechanism recognition.