title: A surface-plasmon-resonance analysis of polylysine interactions with a peptide substrate of protein kinase CK2 and with the enzyme.
abstract: The mechanism of protein kinase CK2 (CK2) activity stimulation by polylysine has been studied by surface plasmon resonance (SPR). The kinetics of the polylysine interaction with a peptide substrate of the enzyme, and with the enzyme itself, have been investigated. A peptide containing a threonine (T) residue surrounded by a cluster of negatively charged acidic [arginine (R) and glutamic acid (E)] residues, RRREEETEEE, and specifically phosphorylated by CK2, was selected. Polylysine interacts with both the enzyme and the peptide substrate. The rate constant, the stoichiometry of the polylysine-peptide substrate interaction and the kinetic parameters of the stimulated enzyme were used to calculate the polylysine-dependent stimulation of CK2. The results are in agreement with experimentally determined polylysine-dependent stimulation. The polylysine-enzyme interaction is too slow to account for enzyme stimulation. The behaviour of polylysine is not reproduced by the polyamine spermine. The results are consistent with a substrate-mediated mechanism of CK2 stimulation by polylysine, and they suggest that the CK2 stimulation by polyamines occurs by a different mechanism.
authors.affiliation: Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Benítez
authors.forename: G
authors.initials: G
authors.lastname: Mier
authors.forename: F
authors.initials: F
authors.lastname: Briones
authors.forename: F J
authors.initials: FJ
authors.lastname: Moreno
authors.forename: J S
authors.initials: JS
authors.lastname: Jiménez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D047390:Casein Kinase II; D002417:Cattle; D004789:Enzyme Activation; D007700:Kinetics; D008956:Models, Chemical; D010446:Peptide Fragments / Q000378:metabolism; D011107:Polylysine / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D013499:Surface Properties
chemical_list: D010446:Peptide Fragments; D011107:Polylysine; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases