title: The binding of cytochrome c to neuroglobin: a docking and surface plasmon resonance study.
abstract: It has recently been proposed that the role of neuroglobin in the protection of neurons from ischaemia induced cell death requires the formation of a transient complex with cytochrome c. No such complex has yet been isolated. Here, we present the results of soft docking calculations, which indicate one major binding site for cytochrome c to neuroglobin. The results yield a plausible structure for the most likely complex structure in which the hemes of each protein are in close contact. NMR analysis identifies the formation of a weak complex in which the heme group of cytochrome c is involved. surface plasmon resonance studies provide a value of 45 microM for the equilibrium constant for cytochrome c binding to neuroglobin, which increases significantly as the ionic strength of the solution increases. The temperature dependence of the binding constant indicates that the complex formation is associated with a small unfavourable enthalpy change (1.9 kcal mol(-1)) and a moderately large, favourable entropy change (14.8 cal mol(-1) deg(-1)). The sensitivity of the binding constant to the presence of salt suggests that the complex formation involves electrostatic interactions.
authors.affiliation: Department of Biological Sciences, University of Aarhus, Aarhus, Denmark.
authors.forename: S H
authors.initials: SH
authors.lastname: Bønding
authors.forename: K
authors.initials: K
authors.lastname: Henty
authors.forename: A J
authors.initials: AJ
authors.lastname: Dingley
authors.forename: T
authors.initials: T
authors.lastname: Brittain
mesh_terms: D000465:Algorithms; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism*; D005914:Globins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism*; D000078787:Neuroglobin; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D012965:Sodium Chloride / Q000494:pharmacology; D020349:Surface Plasmon Resonance; D013696:Temperature
chemical_list: D009419:Nerve Tissue Proteins; D000078787:Neuroglobin; D012965:Sodium Chloride; D005914:Globins; D045304:Cytochromes c