title: Controlling the morphology in DNA condensation and precipitation.
abstract: This work addresses the influence of solution inhomogeneity on conformation, aggregation, and coil/globule and bundle/single chain coexistence of T4 DNA molecules. The inhomogeneity is induced by mixing two solutions containing, respectively, protamine and DNA, with different relative concentrations, but aiming at producing the same final concentrations. The study was conducted by means of fluorescence microscopy (FM), complemented with scanning electron microscopy (SEM). It is shown that the degree of precipitation, the structures formed, and the relative population of compacted and unfolded structures are highly dependent on the method of preparation of the mixtures that contain the DNA/protamine complexes. Most of the structures reported in the literature, that is, overcharged/undercharged globules, toroids, chains internally segregated, and bundles composed of several chains were observed in our different mixtures of fixed final concentration.
authors.affiliation: Chemistry Department, Coimbra University, Rua Larga, Coimbra, Portugal.
authors.forename: Maria F V
authors.initials: MF
authors.lastname: Pinto
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Morán
authors.forename: M Graça
authors.initials: MG
authors.lastname: Miguel
authors.forename: Björn
authors.initials: B
authors.lastname: Lindman
authors.forename: Amália S
authors.initials: AS
authors.lastname: Jurado
authors.forename: Alberto A C C
authors.initials: AA
authors.lastname: Pais
mesh_terms: D017122:Bacteriophage T4 / Q000235:genetics*; D004279:DNA, Viral / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D011479:Protamines / Q000737:chemistry
chemical_list: D004279:DNA, Viral; D011479:Protamines