title: Cytochrome c and organic molecules: solution structure of the p-aminophenol adduct.
abstract: Protein-protein interactions are driven by specific properties of the molecular surfaces. Cytochrome c, a small electron transfer protein, is involved in a number of biologically relevant interactions with macromolecular partners. Small molecules may interfere with such interactions by binding to the surface of cytochrome c. Here we investigated the possibility of weak intermolecular interactions between reduced cytochrome c and a library of 325 small molecules, using WaterLOGSY NMR spectroscopy. Specific binding was found for p-aminophenol. The solution structure of the p-aminophenol-cytochrome c adduct was determined using a combination of in silico tools and NMR-based restraints. The ligand interacts in a specific binding site on the protein surface through a combination of stacking and H-bond interactions. Small but meaningful rearrangements of the solvent-exposed side chains are observed upon ligand binding and contribute to the stabilization of the complex.
authors.affiliation: ProtEra srl, viale delle idee 22, 50019 Sesto Fiorentino, Italy.
authors.forename: Michael
authors.initials: M
authors.lastname: Assfalg
authors.forename: Ivano
authors.initials: I
authors.lastname: Bertini
authors.forename: Rebecca
authors.initials: R
authors.lastname: Del Conte
authors.forename: Andrea
authors.initials: A
authors.lastname: Giachetti
authors.forename: Paola
authors.initials: P
authors.lastname: Turano
mesh_terms: D000627:Aminophenols / Q000737:chemistry*; D001665:Binding Sites; D045304:Cytochromes c / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry; D008024:Ligands; D019906:Nuclear Magnetic Resonance, Biomolecular; D009930:Organic Chemicals / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D012996:Solutions
chemical_list: D000627:Aminophenols; D005656:Fungal Proteins; D008024:Ligands; D009930:Organic Chemicals; D012996:Solutions; D045304:Cytochromes c