Spatiotemporal dynamics of protamine-DNA condensation revealed by high-speed atomic force microscopy.

ABSTRACT: Protamines (PRMs) play a crucial role in sperm chromatin condensation, replacing histones to form nucleo-PRM structures, specifically PRM-DNA complexes. Despite their importance in reproduction, the detailed mechanisms underlying PRM-mediated DNA condensation have remained elusive. In this study, we employed high-speed atomic force microscopy (HS-AFM) to directly visualize the real-time binding dynamics of PRM to DNA under physiological conditions. Our HS-AFM observations reveal that PRM insertion initiating the formation of DNA coils. Further, we observed a heterogeneous spatial distribution of PRM-induced DNA looping. With continuous PRM addition, DNA progresses through a series of folding transitions, forming coiled-like structures that evolve into clockwise spirals, rod-shaped intermed

SUBMITTER: Nishide G 

PROVIDER: S-EPMC11930356 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature