title: NMR studies of protein hydration and TEMPOL accessibility.
abstract: Understanding the mechanisms of the interaction between a protein surface and its outer molecular environment is of primary relevance for the rational design of new drugs and engineered proteins. Protein surface accessibility is emerging as a new dimension of Structural Biology, since NMR methods have been developed to follow how molecules, even those different from physiological ligands, preferentially approach specific regions of the protein surface. Hen egg-white lysozyme, a paradigmatic example of the state of the art of protein structure and dynamics, has been selected as a model system to study protein surface accessibility. Bound water and soluble spin-labels have been used to investigate the interaction of this enzyme, both free and bound to the inhibitor (NAG)(3), with its molecular environment. No tightly bound water molecules were found inside the enzyme active site, which, conversely, appeared as the most exposed to visits from the soluble paramagnetic probe TEMPOL. From the presented set of data, an integrated view of lysozyme surface accessibility towards water and TEMPOL molecules is obtained.
authors.affiliation: Biomolecular Structure Research Center and Department of Molecular Biology, University of Siena, via A. Fiorentina, I-53100, Siena, Italy. niccolai@unisi.it
authors.forename: Neri
authors.initials: N
authors.lastname: Niccolai
authors.forename: Ottavia
authors.initials: O
authors.lastname: Spiga
authors.forename: Andrea
authors.initials: A
authors.lastname: Bernini
authors.forename: Maria
authors.initials: M
authors.lastname: Scarselli
authors.forename: Arianna
authors.initials: A
authors.lastname: Ciutti
authors.forename: Irene
authors.initials: I
authors.lastname: Fiaschi
authors.forename: Stefano
authors.initials: S
authors.lastname: Chiellini
authors.forename: Henriette
authors.initials: H
authors.lastname: Molinari
authors.forename: Piero A
authors.initials: PA
authors.lastname: Temussi
mesh_terms: D001665:Binding Sites; D003497:Cyclic N-Oxides; D004791:Enzyme Inhibitors / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009113:Muramidase / Q000037:antagonists & inhibitors / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013113:Spin Labels; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D003497:Cyclic N-Oxides; D004791:Enzyme Inhibitors; D013113:Spin Labels; D014867:Water; C421864:hen egg lysozyme; D009113:Muramidase; C001803:tempol