title: Gd3+ vibronic side band spectroscopy. New optical probe of Ca2+ binding sites applied to biological macromolecules.
abstract: A new spectroscopic technique is presented for obtaining infraredlike spectra of the binding sites of Ca2+ and other metals in biological macromolecules. The technique, based on the Ca(2+)-like binding properties of Gd3+, utilizes vibronic side bands (VSB) that appear in Gd3+ fluorescence. In the fluorescence spectrum of Gd3+, the separation in photon frequency between a VSB and its electronic origin at approximately 32,150 cm-1 (approximately 311 nm) is a direct measure of the vibrational frequency of a ligand coordinated to Gd3+ ion. As a consequence, the VSB are uncomplicated by molecular vibrations distant from the Gd3+ binding site. The vibrational spectra resulting from the VSB of Gd3+ coordinated to a Ca2+ binding protein, a phospholipid, and DNA are presented.
authors.affiliation: Chemistry Department, New York University, New York 10003.
authors.forename: I E
authors.initials: IE
authors.lastname: Iben
authors.forename: M
authors.initials: M
authors.lastname: Stavola
authors.forename: R B
authors.initials: RB
authors.lastname: Macgregor
authors.forename: X Y
authors.initials: XY
authors.lastname: Zhang
authors.forename: J M
authors.initials: JM
authors.lastname: Friedman
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004492:Edetic Acid / Q000737:chemistry*; D005682:Gadolinium; D010320:Parvalbumins / Q000378:metabolism; D010713:Phosphatidylcholines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D014867:Water
chemical_list: D002135:Calcium-Binding Proteins; D010320:Parvalbumins; D010713:Phosphatidylcholines; D014867:Water; D004247:DNA; D004492:Edetic Acid; D005682:Gadolinium; C017251:1,2-oleoylphosphatidylcholine; D002118:Calcium