RT Journal Article SR Electronic T1 Saturation Transfer Difference Nuclear Magnetic Resonance Spectroscopy As a Method for Screening Proteins for Anesthetic Binding JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 929 OP 935 DO 10.1124/mol.66.4.929 VO 66 IS 4 A1 John H. Streiff A1 Nenad O. Juranic A1 Slobodan I. Macura A1 David O. Warner A1 Keith A. Jones A1 William J. Perkins YR 2004 UL http://molpharm.aspetjournals.org/content/66/4/929.abstract AB The effects of anesthetics on cellular function may result from direct interactions between anesthetic molecules and proteins. These interactions have a low affinity and are difficult to characterize. To identify proteins that bind anesthetics, we used nuclear magnetic resonance saturation transfer difference (STD) spectroscopy. The method is based on the nuclear Overhauser effect between bound anesthetic protons and all protein protons. To establish STD as a method for testing anesthetic binding to proteins, we conducted measurements on a series of protein/anesthetic solutions studied before by other methods. STD was able to identify that volatile anesthetics bind to bovine serum albumin, oleic acid reduces halothane binding to bovine serum albumin, and halothane binds to apomyoglobin but not lysozyme. Using STD, we found that halothane binding to calmodulin is Ca2+-dependent, which demonstrates anesthetic specificity for a protein conformation. Thus, STD is a powerful tool for investigating anesthetic-protein interactions because of its abilities to detect weak binding, to screen a single protein for binding of multiple anesthetics simultaneously, and to detect a change in anesthetic binding caused by conformational changes or competition with other ligands.