Osmolytes are small, chemically diverse, organic solutes that function as an essential component of cellular stress response.  Non-protecting osmolytes destabilize nucleic acid structures, but effects of protecting osmolytes depend on numerous factors including the type of nucleic acid and the complexity of the functional fold.  To begin quantifying protecting osmolyte effects on nucleic acid interactions we used small angle x-ray scattering (SAXS) techniques to monitor DNA duplexes in the presence of sucrose, a commonly used contrast matching agent in SAXS studies of protein-nucleic acid complexes.  Interactions between duplexes were sucrose independent except under high Mg2+ conditions where stacking interactions were disfavored.  The number of excess ions associated with DNA duplexes, reported by anomalous small angle x-ray scattering (ASAXS) experiments, was also sucrose independent.  Our results suggest that ion atmospheres of individual duplexes remain unperturbed by sucrose.  Progress on SAXS analysis protein-nucleic complexes will be discussed.

SAXS measurement of the effects of a protecting osmolyte on DNA ion atmospheres

243rd National Meeting (2012)

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