title: Ca2+ release from caged-Ca2+ alters the FTIR spectrum of sarcoplasmic reticulum.
abstract: Light-induced Ca2+ release from the Ca2+ complex of Nitr-5 altered the FTIR spectra of sarcoplasmic reticulum vesicles and purified Ca(2+)-ATPase preparations. The principal changes seen in difference spectra obtained after and before illumination in the presence of Nitr-5.Ca2+ consisted of an increase in absorbance at 1663 and 1676 cm-1 and a decrease in absorbance at 1653 cm-1. The light-induced changes in FTIR spectra were prevented by vanadate or EGTA, indicating that they were associated with the formation of Ca2E1 enzyme intermediate. Other light-induced changes in the FTIR spectra at 1600-1250 cm-1 were not clearly related to the sarcoplasmic reticulum, and were attributed to photolysis of Nitr-5. The difference absorbance bands are narrow, suggesting that they originate from changes in side chain vibrations, although some changes in secondary structures may also contribute.
authors.affiliation: Department of Biochemistry and Molecular Biology, State University of New York, Health Science Center, Syracuse 13210.
authors.forename: R
authors.initials: R
authors.lastname: Buchet
authors.forename: I
authors.initials: I
authors.lastname: Jona
authors.forename: A
authors.initials: A
authors.lastname: Martonosi
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology; D007700:Kinetics; D010782:Photolysis; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014638:Vanadates / Q000494:pharmacology
chemical_list: C052455:nitr 5; D014638:Vanadates; D004533:Egtazic Acid; D000252:Calcium-Transporting ATPases; D002118:Calcium