Reduced pyridine nucleotides and dicumarol induce a conformational change in NQO1.

(A) Comparison of the ability of antibodies which bind to helix 7 (A180) and antibodies which bind to the C-terminal domain (C-Term) to immunoprecipitate rhNQO1 in the absence and presence of NADH. (B, C) Immunoprecipitation of rhNQO1 with the A180 antibody in the absence and presence of NADH or NADPH. (D) Immunoprecipitation of rhNQO1 by C-Term and A180 antibodies in the absence and presence of dicumarol. (E) The effect of NADH and dicumarol on the migration of rhNQO1 in non-denaturing PAGE. Reaction conditions for immunoprecipitation studies and non-denaturing PAGE are described in Materials and methods.