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. 1988 Jun;53(6):1007–1013. doi: 10.1016/S0006-3495(88)83180-1

Energy transfer as a probe of protein dynamics in the proteins transferrin and calmodulin.

P B O'Hara 1, K M Gorski 1, M A Rosen 1
PMCID: PMC1330280  PMID: 3395656

Abstract

We have initiated an investigation into the usefulness of fluorescence energy transfer in probing protein dynamics. Our analysis involves measuring the energy transfer efficiency while perturbing the protein conformational equilibrium with heat. As the temperature increases, the amplitudes of vibrations increase, and fluorescence energy transfer should also increase if the donor and acceptor are in a flexible region of the protein. A theoretical analysis developed by Somogyi and co-workers for the temperature dependence of dipole-dipole energy transfer (Somogyi, B., J. Matko, S. Papp, J. Hevessey, G. R. Welch, and S. Damjanovich. 1984. Biochemistry. 23:3403-3411) was tested by the authors in one protein system. Energy transfer from tryptophan to a pyridoxamine derivatized side group in RNase increased 40% over 25 degrees C. Here we report further testing of this model in two additional protein systems: calmodulin, a calcium activated regulatory protein, and transferrin, a blood serum iron shuttle. Our studies show a slight differential sensitivity of the transfer efficiency to heat for the two systems. Normalized energy transfer over 6.5 A in calmodulin from a tyrosine donor to a Tb(III) acceptor increases 40% from 295 to 320 K. Normalized energy transfer over 42 A in transferrin from a Tb(III) donor to an Fe(III) acceptor increases 35% over the same temperature range. Whereas these results demonstrate that thermally induced fluctuations do increase energy transfer as predicted by Somogyi, they also appear rather insensitive to the nature of the protein host environment. In contrast to the Förster processes examined above, energy transfer over very short distances has shown an anomalously high temperature dependence.

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Selected References

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  1. Aisen P., Listowsky I. Iron transport and storage proteins. Annu Rev Biochem. 1980;49:357–393. doi: 10.1146/annurev.bi.49.070180.002041. [DOI] [PubMed] [Google Scholar]
  2. Cross A. J., Fleming G. R. Influence of inhibitor binding on the internal motions of lysozyme. Biophys J. 1986 Sep;50(3):507–512. doi: 10.1016/S0006-3495(86)83488-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Dedman J. R., Means A. R. Characterization of a spectrophotometric assay for cAMP phosphodiesterase. J Cyclic Nucleotide Res. 1977 Apr;3(2):139–152. [PubMed] [Google Scholar]
  4. Demchenko A. P. Fluorescence analysis of protein dynamics. Essays Biochem. 1986;22:120–157. [PubMed] [Google Scholar]
  5. Elber R., Karplus M. Multiple conformational states of proteins: a molecular dynamics analysis of myoglobin. Science. 1987 Jan 16;235(4786):318–321. doi: 10.1126/science.3798113. [DOI] [PubMed] [Google Scholar]
  6. Gopalakrishna R., Anderson W. B. Ca2+-induced hydrophobic site on calmodulin: application for purification of calmodulin by phenyl-Sepharose affinity chromatography. Biochem Biophys Res Commun. 1982 Jan 29;104(2):830–836. doi: 10.1016/0006-291x(82)90712-4. [DOI] [PubMed] [Google Scholar]
  7. Haas E., Steinberg I. Z. Intramolecular dynamics of chain molecules monitored by fluctuations in efficiency of excitation energy transfer. A theoretical study. Biophys J. 1984 Oct;46(4):429–437. doi: 10.1016/S0006-3495(84)84040-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Karplus M., McCammon J. A. The internal dynamics of globular proteins. CRC Crit Rev Biochem. 1981;9(4):293–349. doi: 10.3109/10409238109105437. [DOI] [PubMed] [Google Scholar]
  9. Kretsinger R. H., Rudnick S. E., Weissman L. J. Crystal structure of calmodulin. J Inorg Biochem. 1986 Oct-Nov;28(2-3):289–302. doi: 10.1016/0162-0134(86)80093-9. [DOI] [PubMed] [Google Scholar]
  10. O'Hara P. B., Koenig S. H. Electron spin resonance and magnetic relaxation studies of gadolinium(III) complexes with human transferrin. Biochemistry. 1986 Mar 25;25(6):1445–1450. doi: 10.1021/bi00354a038. [DOI] [PubMed] [Google Scholar]
  11. O'Hara P., Yeh S. M., Meares C. F., Bersohn R. Distance between metal-binding sites in transferrin: energy transfer from bound terbium (III) to iron (III) or manganese (III). Biochemistry. 1981 Aug 4;20(16):4704–4708. doi: 10.1021/bi00519a028. [DOI] [PubMed] [Google Scholar]
  12. Somogyi B., Matkó J., Papp S., Hevessy J., Welch G. R., Damjanovich S. Förster-type energy transfer as a probe for changes in local fluctuations of the protein matrix. Biochemistry. 1984 Jul 17;23(15):3403–3411. doi: 10.1021/bi00310a004. [DOI] [PubMed] [Google Scholar]
  13. Stryer L. Fluorescence energy transfer as a spectroscopic ruler. Annu Rev Biochem. 1978;47:819–846. doi: 10.1146/annurev.bi.47.070178.004131. [DOI] [PubMed] [Google Scholar]
  14. Xu G., Weber G. Dynamics and time-averaged chemical potential of proteins: importance in oligomer association. Proc Natl Acad Sci U S A. 1982 Sep;79(17):5268–5271. doi: 10.1073/pnas.79.17.5268. [DOI] [PMC free article] [PubMed] [Google Scholar]

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