Interactions of S100 Proteins with Proteins Kinase Substrates. Biological Implication

摘要: S-100 proteins are a group of low molecular weight (10 kDa) acidic highly concentrated in brain tissues (for recent review see Kligman and Hild, 1988). S100 purified from bovine brain, mixture hetero- homodimer two types subunit, α s with different amino acid composition (Isobe et al., 1977). The sequence the subunits revealed structural relationship calcium binding EF-hand type Okuyama, 1978). Both have one 30-residue putative domain (site I) N-terminal part typical 28-residue II) C-terminal part. Calcium-binding studies on S100αα S100ss (S100b) confirmed presence specific calcium-binding sites per (Baudier 1986a). subunit been studied by means intrinsic fluorescence absorption spectroscopy, Ca2+ analoge Tb3+ H-NMR (in preparation), showed that both cases saturation -binding occured first followed to - site I). In absence monovalent cation affinities II IIs range between 10–20 μM those Iα Is 100–400 μM. physiological intracellular KCl concentrations protein for drastically decrease 500 -1 mM, which become probably not compatible concentrations. However, it has shown may also depend greatly quaternary tertiary structures. Conformational effectors such as Zn2+ ions peculiar case S100b, alkylation Cys 85α or 84s, interaction target were proved increase .5 –10 antagonistic effect 1986a, 1986b, 1987a).