DNA is an ideal polymer for adsorption studies due to the impressive array of biochemical tools available for its synthesis, manipulation, and analysis. In this study, we use hydroxyl radical footprinting to probe the conformation of a single-stranded DNA analog adsorbed to the surface of latex microspheres in water. The DNA molecule has a diblock copolymer architecture with an uncharged block 20 nucleotides in length and an equally long negatively charged block. We find that this model block copolymer does not form a polymer brush layer when adsorbed to negatively charged latex at moderate salt concentrations (0.05 M NaCl). Furthermore, the exact nature of the DNA-surface interaction is found to depend on both the primary charge of the bare latex particles and on the surface density of adsorbed polymer.