A- to B-form transition in DNA between gold surfaces.

Molecular dynamics simulations have been performed to characterize the conformation of DNA that is present when DNA links gold nanoparticles to form nanoparticle superlattice crystals. To model the DNA-linked gold nanoparticles, four strands of DNA are used to connect two gold surfaces, with a small interstrand separation and high added salt to match experiment. A-form DNA was assumed for the initial conformation, as this form of DNA has a length per base-pair that matches lengths that have been inferred from X-ray measurements.