Abstract

Single molecule studies of protamine-DNA interactions have characterized the kinetics of protamine binding to DNA and the morphology of the toroidal subunits that comprise sperm chromatin. The results provided by these studies are reviewed, the advantage of using single molecule techniques is discussed, and the implications of the results to the structure, kinetics of toroid formation, and stability of the DNA-protamine complex are described. New measurements of DNA condensation forces induced by the binding of protamine to DNA are also presented. These forces induce a significant tension in constrained segments of DNA and may contribute to the reduction in volume and shaping of the maturing spermatid cell nucleus.

Keywords: Atomic force microscopy, DNA-protamine interactions, optical trap, single molecule, sperm chromatin, spermiogenesis, transition protein 1, PROTAMINE BINDING KINETICS, chromatin nodules, DNA-protamine toroids, DNA Tension, DNA Condensation Forces, nucleosomes, spermatid, Sperm genomic DNA, Sigma-Aldrich, transmission electron microscopy, salmon protamine, fertilization, anchoring domains, DNA-protamine complexesAtomic force microscopy, DNA-protamine interactions, optical trap, single molecule, sperm chromatin, spermiogenesis, transition protein 1, PROTAMINE BINDING KINETICS, chromatin nodules, DNA-protamine toroids, DNA Tension, DNA Condensation Forces, nucleosomes, spermatid, Sperm genomic DNA, Sigma-Aldrich, transmission electron microscopy, salmon protamine, fertilization, anchoring domains, DNA-protamine complexes