Time-Dependent Decays of Fluorescence Anisotropy

Lakowicz, Joseph R.

doi:10.1007/978-1-4615-7658-7_6

Cited by 21 publications

(27 citation statements)

References 35 publications

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“…1 in mind, we took great care to excite the crystals at their surface during the fluorescence lifetime imaging (FLIM) experiments (although it should be noted that fluorescence decay kinetics are not affected by reabsorption, provided all emitters are spectrally identical). 39 (Fig. 2).…”

Section: Spimmentioning

confidence: 97%

“…P N i¼1 p i , which is directly proportional to the fluorescence quantum yield (and inversely proportional to the extent of quenching). 39 Barros et al 24 used the intensity-weighted average lifetime…”

mentioning

confidence: 99%

“…P N i¼1 p i t i , which is not directly proportional to the fluorescence quantum yield, and the contribution of long-lived components is overestimated relative to that of the short-lived components. 39 When discussing the extent of fluorescence quenching, it is therefore appropriate to use hti amp and not hti int . The difference between hti amp and hti int is illustrated in Table 2.…”

mentioning

confidence: 99%

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Different crystal morphologies lead to slightly different conformations of light-harvesting complex II as monitored by variations of the intrinsic fluorescence lifetime

Oort

Maréchal

Ruban

et al. 2011

Phys. Chem. Chem. Phys.

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In 2005, it was found that the fluorescence of crystals of the major light-harvesting complex LHCII of green plants is significantly quenched when compared to the fluorescence of isolated LHCII (A. A. Pascal et al., Nature, 2005, 436, 134-137). The Raman spectrum of crystallized LHCII was also found to be different from that of isolated LHCII but very similar to that of aggregated LHCII, which has often been considered a good model system for studying nonphotochemical quenching (NPQ), the major protection mechanism of plants against photodamage in high light. It was proposed that in the crystal LHCII adopts a similar (quenching) conformation as during NPQ and indeed similar changes in the Raman spectrum were observed during NPQ in vivo (A. V. Ruban et al., Nature, 2007, 450, 575-579). We now compared the fluorescence of various types of crystals, differing in morphology and age. Each type gave rise to its own characteristic mono-exponential fluorescence lifetime, which was 5 to 10 times shorter than that of isolated LHCII. This indicates that fluorescence is not quenched by random impurities and packing defects (as proposed recently by T. Barros et al., EMBO Journal, 2009, 28, 298-306), but that LHCII adopts a particular structure in each crystal type, that leads to fluorescence quenching. Most interestingly, the extent of quenching appears to depend on the crystal morphology, indicating that also the crystal structure depends on this crystal morphology but at the moment no data are available to correlate the crystals' structural changes to changes in fluorescence lifetime.

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Section: Spimmentioning

confidence: 97%

mentioning

confidence: 99%

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confidence: 99%

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Different crystal morphologies lead to slightly different conformations of light-harvesting complex II as monitored by variations of the intrinsic fluorescence lifetime

Oort

Maréchal

Ruban

et al. 2011

Phys. Chem. Chem. Phys.

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“…The value of R o , and the overlap integral required to calculate the donor-acceptor distances, were determined as described previously [36]. The normalized FRET efficiency, f¢, was defined as [18]:…”

Section: Fluorescence Measurementsmentioning

confidence: 99%

“…The apparent limiting anisotropy (r 0 app ) was determined from the y-intercept of linear fits to the 1/r vs. T/g plots [36], while the value of V was determined from the slopes.…”

Section: Steady-state Anisotropy Measurementsmentioning

confidence: 99%

Dynamic reorganization of the motor domain of myosin subfragment 1 in different nucleotide states

Bódis

Szarka

Nyitrai

et al. 2003

European Journal of Biochemistry

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, were shown to provide an excellent structural framework for using to understand the mechanism of muscle contraction. According to these D. discoideum structures, S1.ADP.BeF x resembles the S1.ATP conformation, whereas S1.ADP.AlF -4 and S1. ADP.V i resemble the S1.ADP.P i conformation. On the other hand, the smooth muscle myosin S1 atomic structures with ADP.BeF x and ADP.AlF -4 were almost identical [7]. Analysis of these atomic models revealed that a key structural part of the nucleotide induced conformational changes in the core of the motor domain is the switch 2 (SWII) element, which consists of the SWII helix (residues 475-509) and the SWII loop (residues 511-520). The SWII element can be in an open or closed conformation in the individual states of the ATPase cycle [8]. The two conformations are in a dynamic equilibrium, which is controlled by the bound nucleotide. The open state is dominant in the pre-and postpower-stroke states, such as the apo-enzyme or S1 with bound ATP or ADP, or in the nucleotide states mimicked by b-c-imidoadenosine 5¢-triphosphate or ATPcS [8]. The closed conformation was attributed to the transition state and was observed with bound ADP.P i analogues, ADP.V i or ADP.AlF -4 . In the ADP.BeF x bound motor domain, both the open and closed conformation could be detected [5,7]. During the open-to-closed transition, the SWII element moves towards the c-phosphate [8]. This transition step can be followed by the hydrolysis of ATP and the closure of the active site through the relative rotation of the 50 kDa upper domain and the 50 kDa lower domain. The helix consisting of residues 648-666 is in the fulcrum of this rotation. In conjunction with this transition, the converter domain rotates by 60°, which induces the movement of the C-terminal end of S1 by 12 nm [9].Tryptophan fluorescence has proved to be a powerful experimental tool when used to characterize the different aspects of myosin interaction with nucleotides [10][11][12][13]. Rapid kinetic experiments using tryptophan fluorescence indicated Correspondence to B. Somogyi,

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Detection of receptor clustering by flow cytometric fluorescence anisotropy measurements

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Time-Dependent Decays of Fluorescence Anisotropy

Cited by 21 publications

References 35 publications

Different crystal morphologies lead to slightly different conformations of light-harvesting complex II as monitored by variations of the intrinsic fluorescence lifetime

Different crystal morphologies lead to slightly different conformations of light-harvesting complex II as monitored by variations of the intrinsic fluorescence lifetime

Dynamic reorganization of the motor domain of myosin subfragment 1 in different nucleotide states

Detection of receptor clustering by flow cytometric fluorescence anisotropy measurements

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