Molecular level probing of preferential hydration and its modulation by osmolytes through the use of pyranine complexed to hemoglobin

Camille J. Roche, Feng Guo, Joel M. Friedman

Research output: Contribution to journalArticle

33 Scopus citations


Two spectroscopic probes are used to expose molecular level changes in hydration shell water interactions that directly relate to such issues as preferential hydration and protein stability. The major focus of the present study is on the use of pyranine (HPT) fluorescence to probe as a function of added osmolytes (PEG, urea, trehalose, and magnesium), the extent to which glycerol is preferentially excluded from the hydration shell of free HPT and HPT localized in the diphosphoglycerate (DPG) binding site of hemoglobin in both solution and in Sol-Gel matrices. The pyranine study is complemented by the use of vibronic side band luminescence from the gadolinium cation that directly exposes the changes in hydrogen bonding between first and second shell waters as a function of added osmolytes. Together the results form the basis for a water partitioning model that can account for both preferential hydration and water/osmolyte-mediated conformational changes in protein structure.

Original languageEnglish (US)
Pages (from-to)38757-38768
Number of pages12
JournalJournal of Biological Chemistry
Issue number50
Publication statusPublished - Dec 15 2006


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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