Europium(III) laser luminescence excitation spectroscopy of calcium-modulated proteins: Parvalbumin and calmodulin

Horrocks, William DeW.; Mulqueen, Paul; Rhee, Moo-Jhong; Breen, Patrick J.; Hild, E.

doi:10.1016/s0020-1693(00)95044-8

Cited by 4 publications

(4 citation statements)

References 13 publications

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“…Forster-Type Nonradiative Energy-Transfer Distance Measurement between Eu(IIf) and Nd(IH) in the Two Tight Sites. In order to further characterize calmodulin structurally, we have carried out energy-transfer distance measurements between an energy donor ion, Eu(III), and an energy acceptor ion, Nd(III), employing some refinements over our previously described procedures (Horrocks et al, 1980(Horrocks et al, , 1983Rhee et al, 1981;Snyder et al, 1981). Since calmodulin binds the first two equivalents of added Ln(III) ions quantitatively, we have restricted our distance measurements to calmodulin to which a 19:1 ratio of Nd(III) to Eu(III) has been added to a total of 2 equiv.…”

Section: Potential Differences In Lifetimes and Emission Spectra Betweenmentioning

confidence: 99%

“…There have been a large number of studies of Ca(II) ion binding to CaM (Haiech et al, 1981;Kohse & Heilmeyer, 1981;Cox et al, 1981; Burger et al, 1983;Potter et al, 1983; Cox, 1984) as well as of substitutional probes such as Cd(II) (Forsen et al, 1980;Andersson et al, 1982Andersson et al, , 1983a, Gd(III) (Krebs & Carafoli, 1982), Tb(III) (Kilhoffer et al, 1980a,b;Wang et al, 1982; Wallace et al, 1982), and Eu(III) (Wang et al, 1982;Horrocks et al, 1983). Something less than universal agreement exists with regard to the values of the binding constants and the order (if any) with which various fThis research was supported by National Institutes of Health Grant GM-23599.…”

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confidence: 99%

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Characterization of lanthanide(III) ion binding to calmodulin using luminescence spectroscopy

Mulqueen¹,

Tingey²,

Horrocks³

1985

Biochemistry

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Pulsed dye laser excitation spectroscopy of the 7F0----5D0 transition of Eu(III) reveals only a single peak as this ion is titrated into apocalmodulin. A titration based on the intensity of this transition shows that the first two Eu(III) ions bind quantitatively to two tight sites, followed by weaker binding (Kd = 2 microM) to two additional sites under conditions of high ionic strength (0.5 M KC1). This excitation experiment is also shown to be a general method for measuring contaminating levels of EDTA down to 0.2 microM in proton solutions. Experiments with Tb(III) using both direct laser excitation and indirect sensitization of Tb(III) luminescence through tyrosine residues in calmodulin also give evidence for two tight and two weaker binding sites (Kd = 2-3 microM). The indirect sensitization results primarily upon binding to the two weaker sites, implying that Tb(III) binds first to domains I and II, which are remote from tyrosine-containing domains III and IV. The 7F0----5D0 excitation signal of Eu(III) was used to measure the relative overall affinities of the tripositive lanthanide ions, Ln(III), across the series. Ln(III) ions at the end of the series are found to bind more weakly than those at the beginning and middle of the series. Eu(III) excited-state lifetime measurements in H2O and D2O reveal that two water molecules are coordinated to the Eu(III) at each of the four metal ion binding sites. Measurements of Förster-type nonradiative energy-transfer efficiencies between Eu(III) and Nd(III) in the two tight sites were carried out by monitoring the excited-state lifetimes of Eu(III) in the presence and absence of the energy acceptor ion Nd(III).(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Potential Differences In Lifetimes and Emission Spectra Betweenmentioning

confidence: 99%

mentioning

confidence: 99%

Characterization of lanthanide(III) ion binding to calmodulin using luminescence spectroscopy

Mulqueen¹,

Tingey²,

Horrocks³

1985

Biochemistry

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“…Parvalbumin, being structurally well characterized and simpler than calmodulin or troponin C, each of which contains four metal ion binding sites, is the most suitable candidate for definitive studies in this area. Previous studies (Benzonana et al, 1972;Donato & Martin, 1974;Nelson et al, 1977;Sowadski et al, 1978;Cavé et al, 1979;Haiech et al, 1979a; Horrocks & Collier, 1981;Rhee et al, 1981;Lee & Sykes, 1981;Horrocks et al, 1983;Corson et al, 1983a,b;Williams et al, 1984) have resulted in a controversy regarding whether the filling of the CD and EF metal ion binding sites occurs in a simultaneous or sequential fashion during metal ion titration experiments and whether there is any cooperativity between the sites. The present paper and the following one (Breen et al, 1985) provide a variety of spectroscopic and kinetic data which address these important questions.…”

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Spectroscopic studies of metal ion binding to a tryptophan-containing parvalbumin

Breen¹,

Hild²,

Horrocks³

1985

Biochemistry

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The binding of Ca(II) and members of the trivalent lanthanide ion, Ln(III), series to apoparvalbumin (isotype pI = 4.75) from codfish (Gadus callarius L) results in the development of a distinctive sharp feature in the UV absorption spectrum at about 290 nm. Titration curves obtained by monitoring the spectral change in this region reveal a change in slope after the addition of 1 equiv of metal ion and no further rise after 2 equiv has been added, consistent with sequential binding to the principal EF and CD sites. Laser-induced luminescence excitation spectra of the 7F0----5D0 transition of bound Eu(III) demonstrate the quantitative binding of this ion to the principal sites and disclose the presence of a subsidiary site at pH values greater than 6. Metal ion competition experiments monitored by means of this excitation transition show that the early members of the Ln(III) ion series bind more tightly than those at the end. Tryptophan-sensitized Tb(III) luminescence reveals that this ion binds sequentially to the EF and CD sites, in that order. The intrinsic tryptophan fluorescence of apoparvalbumin is increased in a stepwise fashion as Ca(II) or Ln(III) ions bind sequentially, with the exceptions of Eu(III) and Yb(III). The binding of the latter two ions causes quenching of the protein fluorescence via an energy-transfer process which involves low-lying charge-transfer bands. The distance dependences of the tryptophan to Tb(III) and tryptophan to Eu(III) energy-transfer processes are observed to be identical, consistent with a Förster-type mechanism in both cases.

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“…An increase in temperature to 25 °C increases the amount of the CoSCN+ complex relative to that of the bis and tris forms. At 15 °C approximately 20% of the Co(II) exists as the aquo ion, and this increases to about 30% at 25 °C. There will be no measurable concentration of the tetrakis complex.…”

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Photochemistry of nickel(II) azido complexes: singlet nitrene

Ngai¹,

Wang²,

Reed³

1985

Inorg. Chem.

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Europium(III) laser luminescence excitation spectroscopy of calcium-modulated proteins: Parvalbumin and calmodulin

Cited by 4 publications

References 13 publications

Characterization of lanthanide(III) ion binding to calmodulin using luminescence spectroscopy

Characterization of lanthanide(III) ion binding to calmodulin using luminescence spectroscopy

Spectroscopic studies of metal ion binding to a tryptophan-containing parvalbumin

Photochemistry of nickel(II) azido complexes: singlet nitrene

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