title: Dimethyl sulfoxide binding to globular proteins: a nuclear magnetic relaxation dispersion study.
abstract: The 2H magnetic relaxation dispersion (NMRD) technique was used to characterize interactions of dimethyl sulfoxide (DMSO) with globular proteins. A difference NMRD experiment involving the N-acetylglucosamine trisaccharide inhibitor, demonstrated that the DMSO 2H NMRD profile in lysozyme solution is due to a single DMSO molecule bound in the active cleft, with a molecular order parameter of 0.47 +/- 0.05 and a residence time in the range 10 ns to 5 ms. With the aid of transverse 2H relaxation data, the upper bound of the residence time was further reduced to 100 microns. A 1H shift titration experiment was also performed, yielding a binding constant of 2.3 +/- 0.3 M-1 at 27 degrees C. In contrast to lysozyme, no DMSO dispersion was observed for bovine pancreatic trypsin inhibitor (BPTI), indicating that a stable DMSO-protein complex requires a cleft of appropriate geometry in addition to hydrogen-bond and hydrophobic interactions.
authors.affiliation: Condensed Master Magnetic Resonance Group, Department of Chemistry, Lund University, Sweden. haukur.johannesson@fkem2.lth.se
authors.forename: H
authors.initials: H
authors.lastname: Jóhannesson
authors.forename: V P
authors.initials: VP
authors.lastname: Denisov
authors.forename: B
authors.initials: B
authors.lastname: Halle
mesh_terms: D007611:Aprotinin / Q000737:chemistry / Q000378:metabolism*; D003903:Deuterium; D004121:Dimethyl Sulfoxide / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism*; D009844:Oligosaccharides / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D009844:Oligosaccharides; D007611:Aprotinin; D003903:Deuterium; D009113:Muramidase; D004121:Dimethyl Sulfoxide