title: Thermodynamics of apocalmodulin and nitric oxide synthase II peptide interaction.
abstract: The Ca2+-free form of calmodulin (CaM), apocalmodulin (ApoCaM), regulates a variety of target proteins including nitric oxide synthase II (NOS-II). The CaM-binding site of NOS-II can bind ApoCaM with high affinity. Substitution of hydrophobic amino acids by charged amino acids at crucial positions 3, 9 and 13 within the CaM-binding motif did not abolish the ApoCaM interaction that occurred with significant affinity, though the affinity of the interaction was decreased remarkably. Isothermal titration calorimetry revealed that interaction of ApoCaM and synthetic NOS-II peptides was driven entropically.
authors.affiliation: Institut für Biologische Informationsverarbeitung 1, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Censarek
authors.forename: Michael
authors.initials: M
authors.lastname: Beyermann
authors.forename: Karl-Wilhelm
authors.initials: KW
authors.lastname: Koch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001059:Apoproteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D002151:Calorimetry; D019277:Entropy; D057927:Hydrophobic and Hydrophilic Interactions; D008264:Macrophages / Q000201:enzymology; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D019001:Nitric Oxide Synthase / Q000737:chemistry / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: D001059:Apoproteins; D002147:Calmodulin; D010455:Peptides; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II