Fig. 2
Topology-dependent contributions to the folding of a DNA origami. aThe full DNA origami structure is composed of three quasi-independent domains (A, B, and C) of identical shape but distinct sequence content, leading to four types of global isomers (b), wherein only the conformation, but not the identity, of the individual domains can be distinguished (c or i, for canonical or isomerized, respectively). c AFM characterization of the global structure in absence (e(−) construct) or presence of edges type 0, 1, or 2 (e(0), e(1), and e(2) constructs), either on the left- (L) or right-side (R) of each domain (upper and lower panels, respectively). Scale bars are 600 nm. Insets are 1 μm × 1 μm. Statistical AFM analysis of the end products is reported in the bar diagram as fraction of domains observed in the iso I or iso II shape (e(−) construct in dark gray bars; left- and right-side edges are indicated respectively in light gray and orange bars). d Statistical AFM analysis of the full DNA origami structure in the absence (e(−)) or presence of both the left- and right-side edges of type 0, 1, or 2. The highest degree of isomerization is given by design e(0) with ca. 11%, 72%, and 11% of global structures appearing as icc, iic, and iii isomers, respectively, and corresponding to ca. 62% of total iso II domains. e Atomic models of the e(0) edges on the right- and left-side of each domain (upper and lower panel, respectively) suggest that hybridization of edge staples to the scaffold generates a torque (τ) that is proportional to the length of the lever arm (gray vector, r), the force applied (yellow vector, F) and their angular displacement (θ) from the ideal coplanar position (for which θ = 0). r and F modules correspond to the lengths of the duplexes formed by the edge staple and the scaffold and located respectively upstream or downstream the crossover. Error bars were obtained from three independent images of the same sample, each showing several hundreds of individual structures. Source data are provided as a Source Data file
