Identification of protein surfaces by NMR measurements with a pramagnetic Gd(III) chelate.
Gd-diethylenetriamine pentaacetic acid-bismethylamide, Gd(DTPA-BMA), is shown to be a reagent suitable for the identification of protein surfaces. Compared to the conventionally used spin-label TEMPOL, Gd(DTPA-BMA) is a stronger relaxation agent, requiring lesser concentrations to achieve the same paramagnetic relaxation enhancement of solvent-exposed protein protons. It is also less hydrophobic and therefore less prone to specific binding to proteins. Relaxation enhancements predicted by a second-sphere interaction model correlated with experimental data recorded with ubiquitin, while the correlation with corresponding data recorded with TEMPOL was poor.
Pintacuda
Guido
G
Department of Medical Biochemistry and Biophysics, Karolinska Institute, Tomtebodavägen 6, S-171 77 Stockholm, Sweden.
Otting
Gottfried
G
D002614:Chelating Agents / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry; D019786:Gadolinium DTPA / Q000737:chemistry*; D006801:Humans; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*; D013113:Spin Labels; D013499:Surface Properties; D025801:Ubiquitin / Q000737:chemistry
D002614:Chelating Agents; D003497:Cyclic N-Oxides; D011506:Proteins; D013113:Spin Labels; D025801:Ubiquitin; C064925:gadodiamide; D019786:Gadolinium DTPA; C001803:tempol