Optically Detected Magnetic Resonance of the Tryptophan Phosphorescent State in Native Proteins*

Zuclich, Joseph A.; Schweitzer, Dieter; Maki, August H.

doi:10.1111/j.1751-1097.1973.tb06407.x

Cited by 46 publications

(22 citation statements)

References 19 publications

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“…Fluorescence, phosphorescence spectra, and the zero-field splitting parameters D and E of the triplet state were determined at 1. 3K with an apparatus (31) for optical detection of magnetic resonance (ODMR) which was similar to the one described by Zuclich et al (32). (23,25).…”

Section: Methodsmentioning

confidence: 99%

Electronic Interactions Between Polycyclic Arenes in Cyclophanes

Haenel

Schweitzer

1987

Advances in Chemistry

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Section: Methodsmentioning

confidence: 99%

Electronic Interactions Between Polycyclic Arenes in Cyclophanes

Haenel

Schweitzer

1987

Advances in Chemistry

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“…At 1.5 K the meth· od used was the analysis of phosphorescence transients after a saturating fast passage [37,38). The ODMR apparatus was in prinCiple the same as described by Zuc1ich et al [39). Beside the zero field splitting parameters also the relative steady.…”

Section: Methodsmentioning

confidence: 99%

Transannular interactions in [2,2] phanes as studied by magnetic resonance and optical spectra

Schweitzer¹,

Colpa²,

Behnke³

et al. 1975

Chemical Physics

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The interaction of IT-eleetrons in [2.2] phanes was studied both experimcntally and theoretically. The fluorescence and phosphorescence spectra were measured at liquid helium temperature; in addition, the zero field splitting parameters D and E were detcrmined by ODMR in zero field and by ordinary ESR at X·band. The results for the phanes with two identical aromatic units can be summarized as follows: The rather small reduction of the D and E values of the order of 10% with respect to the monomrrs indicates, in agreement with the theoretical treatment given in part II, that the two unpaired electrons of the excited triplet state have a high probability to be at a given time in the same half of the molecule. While the fluorescence spectra show the typical behaViour of emission spectra of dimers or excimers, the phosphorescence spectra CKhibit some remaining structure. This behaviour which indicates a somewhat weaker coupling among the triplet orbitals as compared to the singlet orbitals can also be understood on the basis of theoretical considerations. for a phane with two different aromatic units thl! behaviour is found t~ be more Similar to the corresponding aromatic monomer with the lower ex" cited states with some pcrtu~bation by the other part of the phane also.in agreement with theoretical expectation.

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“…. The latter is assumed in that the reverse intersystem crossing undoubtedly occurs from one of the three triplet sublevels which couples most strongly to the singlet state through spin-orbit coupling (Kwiram, 1967;Zulich et al, 1973). The values we present for the intersystem crossing could be regarded, however, as the harmonic mean of the foward and reverse processes.…”

Section: T 5760cmentioning

confidence: 84%

Perturbations to the intersystem crossing of proflavin upon binding to DNA and poly d(A-IU) from triplet-delayed emission spectroscopy

Lee¹,

Galley²

1988

Biophysical Journal

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The steady-state prompt fluorescence, phosphorescence and delayed fluorescence spectra and triplet lifetimes of free proflavin and proflavin bound to native DNA and alternating poly d(A-IU) were obtained as a function of temperature in a buffer-glycerol solvent. The intensity of the proflavin E-type delayed fluorescence (DF) relative to both the phosphorescence (Ph) and the prompt fluorescence (F) was observed to increase with temperature, and plots of both ln (DF/Ph) and ln (DF/(F.tau T] as a function of 1/T were linear over a wide range of temperatures. Although the activation energies for the thermal repopulation of the proflavin excited singlet state from the triplet obtained from the slopes of these plots were essentially unchanged on binding, perturbations to the S1----T1 intersystem crossing rate constants extracted from the intercepts at infinite temperature were observed. The marked enhancement of the intersystem crossing that occurs with binding to the iodinated polynucleotide reflects an external heavy atom perturbation upon the intercalated dye which also induces a shortening in the triplet lifetime. With proflavin bound to DNA an enhancement to the S1----T1 intersystem crossing, though lesser in magnitude than for poly d(A-IU), is observed but with no change to the triplet lifetime. The well-studied fluorescence quenching of DNA-bound proflavin is a result of this increase in the intersystem crossing. It is proposed that these non-heavy atom enhancements in the intersystem crossing are due to distortions of the molecular plane of the bound proflavin molecule. In total these analyses provide a complete description of the excited state processes of the proflavin molecule and their variations with temperature.

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Optically Detected Magnetic Resonance of the Tryptophan Phosphorescent State in Native Proteins*

Cited by 46 publications

References 19 publications

Electronic Interactions Between Polycyclic Arenes in Cyclophanes

Electronic Interactions Between Polycyclic Arenes in Cyclophanes

Transannular interactions in [2,2] phanes as studied by magnetic resonance and optical spectra

Perturbations to the intersystem crossing of proflavin upon binding to DNA and poly d(A-IU) from triplet-delayed emission spectroscopy

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