Conformational Heterogeneity of Tryptophan in a Protein Crystal

Dahms, Tanya E. S.; Willis, Kevin; Szabo, Arthur G.

doi:10.1021/ja00113a021

Cited by 71 publications

(56 citation statements)

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“…It is noteworthy that TOE exhibits double exponential fluorescence decay in all the solvents examined. This behaviour is reminiscent of tryptophan (which exhibits nonexponential decay in water) (16,27,28). Like tryptophan, the presence of three rotamers about the C ␣ OC ␤ bond (structure shown in Scheme 1) (16,27,28), gives TOE a structural heterogeneity, which would account for the nonexponential decay of TOE in homogeneous solutions.…”

Section: Resultsmentioning

confidence: 95%

Influence of Reverse Micellar Environments on the Fluorescence Emission Properties of Tryptophan Octyl Ester

Sengupta

2000

Biochemical and Biophysical Research Communications

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Section: Resultsmentioning

confidence: 95%

Influence of Reverse Micellar Environments on the Fluorescence Emission Properties of Tryptophan Octyl Ester

Sengupta

2000

Biochemical and Biophysical Research Communications

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“…The aromatic residues (Phe, Tyr, Trp, His) by contrast show little or no correlation with resolution of either the mean values or the relative percentage rotamer population densities. Although other experimental evidence such as NMR (Wu È thrich, 1986) and time-resolved¯uorescent decay of tryptophan (Dahms et al, 1995) have indicated some conformational heterogeneity and ring¯ipping of the aromatics, these residues have been assumed to enhance protein stability because they can close pack in the protein core with far less reduction in side-chain entropy. In electron-density maps from Xray crystallography, the rings are generally clear and well de®ned, and so the tracing is usually unambiguous even at the lower end of the resolution range 3.4.6.…”

Section: Comparison With Data From Peptides and Atomic Resolution Strmentioning

confidence: 99%

Protein side-chain conformation: a systematic variation of χ₁mean values with resolution – a consequence of multiple rotameric states?

MacArthur

Thornton

1999

Acta Crystallogr D Biol Cryst

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A systematic variation with resolution of the mean values of the gauche À , trans and gauche + 1 1 rotamers in protein structures determined by X-ray crystallography has been observed. Further analysis revealed that these correlations differ considerably between residue types, being highly signi®cant for some residue types (e.g. Ser, Thr, Leu, Lys) and absent for others (e.g. aromatics). For the individual residue types which exhibited the trend most strongly, these changes were accompanied by corresponding systematic variations in the percentage relative populations in the three energy wells. Examination of a uniformly sized subset of monomers showed that this effect, while attenuated, was still present, and was thus not entirely a consequence of the change in size and surface area which also correlates with resolution. An analysis of B values in the disfavoured high-energy barrier region between the rotameric wells showed a pronounced tendency towards larger than average values. As a plausible hypothesis, it is suggested here that these observations can be accounted for by the presence of multiple rotameric states. The averaged electron density produced by dual occupancy at low resolution giving an averaged conformation is resolved at high resolution into its individual components.

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“…Willis et al (1991) have followed the¯uorescence decay kinetics of tryptophan residues in myoglobin to probe long-range intra-and intermolecular interactions between tryptophyl residues and the heme. In their study of erabutoxin b crystals, Dahms et al (1995) revealed the presence of multiple conformations of tryptophan residues, although a single conformation had been modelled in the structure.…”

Section: Introductionmentioning

confidence: 99%

Advances in spectroscopic methods for biological crystals. 1. Fluorescence lifetime measurements

et al. 2007

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Absorption microspectrophotometry has been shown to be of considerable help to probe crystalline proteins containing chromophores, metal centres, or coloured substrates/co-factors. Absorption spectra contribute to the proper interpretation of crystallographic structures, especially when transient intermediate states are studied. Here it is shown that¯uorescence microspectrophotometry might also be used for such purposes if endogenous¯uorophores are present in the macromolecule or when exogenous¯uorophores are added and either bind to the protein or reside in the solvent channels. An off-line microspectrophotometer that is able to perform low-temperature absorption and¯uorescence spectroscopy on crystals mounted in cryo-loops is described. One-shot steady-state emission spectra of outstanding quality were routinely collected from several samples. In some cases, crystals with optical densities that are too low or too high for absorption studies can still be tackled with uorescence microspectrophotometry. The technique may be used for simple controls such as checking the presence, absence or redox state of a¯uorescent substrate/co-factor. Potential applications in the ®eld of kinetic crystallography are numerous. In addition, the possibility to probe key physico-chemical parameters of the crystal, such as temperature, pH or solvent viscosity, could trigger new studies in protein dynamics.

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Conformational Heterogeneity of Tryptophan in a Protein Crystal

Cited by 71 publications

References 0 publications

Influence of Reverse Micellar Environments on the Fluorescence Emission Properties of Tryptophan Octyl Ester

Influence of Reverse Micellar Environments on the Fluorescence Emission Properties of Tryptophan Octyl Ester

Protein side-chain conformation: a systematic variation of χ₁mean values with resolution – a consequence of multiple rotameric states?

Advances in spectroscopic methods for biological crystals. 1. Fluorescence lifetime measurements

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Conformational Heterogeneity of Tryptophan in a Protein Crystal

Cited by 71 publications

References 0 publications

Influence of Reverse Micellar Environments on the Fluorescence Emission Properties of Tryptophan Octyl Ester

Influence of Reverse Micellar Environments on the Fluorescence Emission Properties of Tryptophan Octyl Ester

Protein side-chain conformation: a systematic variation of χ1mean values with resolution – a consequence of multiple rotameric states?

Advances in spectroscopic methods for biological crystals. 1. Fluorescence lifetime measurements

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Protein side-chain conformation: a systematic variation of χ₁mean values with resolution – a consequence of multiple rotameric states?