Spatial organization of Dps and DNA–Dps complexes

Abstract DNA co-crystallization with Dps family proteins is a fundamental mechanism, which preserves in bacteria from harsh conditions. Though many aspects of this phenomenon are well characterized, the spatial organization DNA–Dps co-crystals not completely understood, and existing models need further clarification. To advance problem we have utilized atomic force microscopy (AFM) as main structural tool, small-angle X-scattering (SAXS) to characterize key component DNA-protein complex. SAXS analysis presence EDTA indicates significantly larger radius gyration for than would be expected core dodecamer, consistent N-terminal regions extending out into solution being accessible interaction DNA. In AFM experiments, both protein molecules complexes adsorbed on mica or highly oriented pyrolytic graphite (HOPG) surfaces form densely packed hexagonal structures characteristic size about 9 nm. shed light peculiarities molecules, characterized individual complexes. Contour length evaluation has confirmed non-specific character binding revealed that does wrap Angle demonstrated molecule contacts segment ~6 nm length. Consideration condensation upon complex formation small quasi-crystals may arranged along rows ordered sheet.