Multiple conformational states in myoglobin revealed by frequency domain fluorometry

Bismuto, Ettore; Irace, Gaetano; Gratton, Enrico

doi:10.1021/bi00430a013

Cited by 32 publications

(16 citation statements)

References 35 publications

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“…It is worthy of note that the corrected fractional increase observed for wild-type apomyoglobin is practically coincident with the sum of the yield increases of the protein mutants containing a single tryptophanyl residue. The fractional increase determined for the complex between ANS and tuna apomyoglobin, a protein that contains a single tryptophan at position 14 (12,28,29), was 0.680, a value similar to that found for the sperm whale mutant containing only W14. The fractional increase exceeding that of the reference mutant depends on the transfer efficiency Q T and on the ratio between the absorption coefficients of the donor at 295 nm and acceptor at 350 nm, i.e.…”

Section: Resultssupporting

confidence: 75%

Resolution of Tryptophan–ANS Fluorescence Energy Transfer in Apomyoglobin by Site-directed Mutagenesis¶

Sirangelo¹,

Malmo²,

Casillo³

et al. 2002

Photochem Photobiol

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Resonance energy transfer between tryptophanyl residues and the apolar fluorescent dye 1-anilino-8-naphthalene sulfonate (ANS) occurs when the fluorophore is bound to native folded sperm whale apomyoglobin. The individual transfer contribution of the two tryptophanyl residues (W7 and W14, both located on the A-helix of the protein) was resolved by measuring the tryptophan-ANS transfer efficiency for the ANS-apomyoglobin complexes formed by wild-type protein and protein mutants containing one or no tryptophanyl residues, i.e. W7F, W14F and W7YW14F. The transfer efficiency of W14 residue was found to be higher than that of W7, thus indicating that W14 acts as the main energy donor in the ANS-apomyoglobin complex. This suggests that the plane containing the anilinonaphthalene ring of the extrinsic fluorophore has a spatial orientation similar to that of W14 and, hence, to the heme group in the holoprotein.

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Section: Resultssupporting

confidence: 75%

Resolution of Tryptophan–ANS Fluorescence Energy Transfer in Apomyoglobin by Site-directed Mutagenesis¶

Sirangelo¹,

Malmo²,

Casillo³

et al. 2002

Photochem Photobiol

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View full text Add to dashboard Cite

show abstract

“…It is worthy of note that the corrected fractional increase observed for wild‐type apomyoglobin is practically coincident with the sum of the yield increases of the protein mutants containing a single tryptophanyl residue. The fractional increase determined for the complex between ANS and tuna apomyoglobin, a protein that contains a single tryptophan at position 14 (12,28,29), was 0.680, a value similar to that found for the sperm whale mutant containing only W14. The fractional increase exceeding that of the reference mutant depends on the transfer efficiency Q T and on the ratio between the absorption coefficients of the donor at 295 nm and acceptor at 350 nm, i.e.…”

Section: Resultssupporting

confidence: 69%

Resolution of Tryptophan-ANS Fluorescence Energy Transfer in Apomyoglobin by Site-directed Mutagenesis¶

Sirangelo¹,

Malmo²,

Casillo³

et al. 2007

Photochemistry and Photobiology

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Resonance energy transfer between tryptophanyl residues and the apolar fluorescent dye 1‐anilino‐8‐naphthalene sulfonate (ANS) occurs when the fluorophore is bound to native folded sperm whale apomyoglobin. The individual transfer contribution of the two tryptophanyl residues (W7 and W14, both located on the A‐helix of the protein) was resolved by measuring the tryptophan–ANS transfer efficiency for the ANS–apomyoglobin complexes formed by wild‐type protein and protein mutants containing one or no tryptophanyl residues, i.e. W7F, W14F and W7YW14F. The transfer efficiency of W14 residue was found to be higher than that of W7, thus indicating that W14 acts as the main energy donor in the ANS–apomyoglobin complex. This suggests that the plane containing the anilinonaphthalene ring of the extrinsic fluorophore has a spatial orientation similar to that of W14 and, hence, to the heme group in the holoprotein.

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“…The emission decay of intrinsic or extrinsic fluorophores bound to apomyoglobin is dependent on the number of such subconformations as well as on the interconversion rate among these substates. Recent studies demonstrated that the tryptophanyl fluorescence emission of apomyoglobin as well as that of 2,6-p-toluidinenaphthalene sulfonate bound to the heme pocket of the apoprotein can be represented by a quasi continuous-lifetime distribution Bismuto et al, 1989a;1989b). More recently, it was shown that the tryptophanyl fluorescence decays of fully unfolded polypeptides are characterized by broader lifetime distributions whose width at half maximum is logarithmically related to the polypeptide chain length (Bismuto et al, 1991).…”

mentioning

confidence: 99%

Structure and dynamics of the acidic compact state of apomyoglobin by frequency‐domain fluorometry

Bismuto¹,

Gratton

Sirangelo³

et al. 1993

European Journal of Biochemistry

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The conformational dynamic properties of tuna apomyoglobin, a single tryptophan-containing protein, in the acidic compact state, as well as in the native and in the fully unfolded state, have been explored by frequency-domain fluorometry. Apomyoglobin at acidic pH in the presence of high salt concentration displays bimodal tryptophanyl lifetime distributions which may be related to the simultaneous presence of different populations of structural states (compact and fully unfolded states). The tryptophanyl anisotropy decay indicated that the acidic compact state displays at least two rotational correlational times, suggesting that this state possesses a complex geometrical organization. 1-Anilino-8-naphthalene sulfonate (ANS), bound both to native and compact protein forms, shows broad unimodal lifetime distributions. The small time dependence of the ANS emission spectra indicated that the solvent dipolar reorganization are either absent or they occur on a time scale much shorter than the lifetime of the excited ANS molecule bound to apomyoglobin. The anisotropy decay data relative to the extrinsic fluorophore (ANS) are consistent with the presence of a single rotational correlation time for both native (12.1 ns) and compact (6.2 ns) states.

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Multiple conformational states in myoglobin revealed by frequency domain fluorometry

Cited by 32 publications

References 35 publications

Resolution of Tryptophan–ANS Fluorescence Energy Transfer in Apomyoglobin by Site-directed Mutagenesis¶

Resolution of Tryptophan–ANS Fluorescence Energy Transfer in Apomyoglobin by Site-directed Mutagenesis¶

Resolution of Tryptophan-ANS Fluorescence Energy Transfer in Apomyoglobin by Site-directed Mutagenesis¶

Structure and dynamics of the acidic compact state of apomyoglobin by frequency‐domain fluorometry

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