FIGURE 3.

Typical diffraction spectrum of the dense DNA precipitate. The diffracted intensity profile has been obtained by radial integration. The first intense peak is due to the lateral hexagonal arrangement of the DNA chains in the plane perpendicular to the double-helix axis. The interaxial spacing a_H between two neighboring DNA (insert) is determined from this peak position q₁₁₀ via the equation a_H = (2π / q₁₁₀) × (2/√3). The second peak (q₁₁₁) comes from a longitudinal order between the double helices. This profile was obtained from a spermine-DNA sample diluted in a 6 mM spermine salt solution.