title: A subnanosecond-pulse fluorometric study of the CA2+ and MG2+ induced conformational changes on S-100a protein.
abstract: The fluorescence parameters of the single tryptophan residue (Trp 90 alpha) in S-100a (alpha beta) protein have been studied by steady state fluorimetry and by subnanosecond fluorescence decays excited by pulsed-picosecond laser system. At pHs 7.1 and 8.5, double exponential decays were consistently observed. At both pHs, Ca2+ and to a less extent Mg2+ ions proved to modify the percentage contribution of the two decaying species. The interest of the finding is discussed.
mesh_terms: D000818:Animals; D015415:Biomarkers; D001921:Brain / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D011487:Protein Conformation; D009418:S100 Proteins / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013997:Time Factors; D014364:Tryptophan / Q000032:analysis
chemical_list: D015415:Biomarkers; C030564:S-100 calcium-binding protein alpha subunit; D009418:S100 Proteins; D014364:Tryptophan; D008274:Magnesium; D002118:Calcium