Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1993 Jun 15;90(12):5443–5445. doi: 10.1073/pnas.90.12.5443

Electron self-exchange in azurin: calculation of the superexchange electron tunneling rate.

K V Mikkelsen 1, L K Skov 1, H Nar 1, O Farver 1
PMCID: PMC46736  PMID: 8516286

Abstract

Electronic coupling between the copper atoms in an azurin dimer has been calculated in this conformationally well-defined system by using many-electronic wave functions. When one of the two water molecules forming intermolecular hydrogen bonds between the copper-ligating His-117 of the two azurins is removed, the calculated coupling element is reduced from 2.5 x 10(-6) to 1.1 x 10(-7) eV (1 eV = 1.602 x 10(-19) J). Also, the effects of the relative orientations of the two water molecules have been analyzed. The results show that water molecules may play an important role as switches for biological electron transfer. The rate of electron self-exchange between two azurins has been calculated, and the result is in very good agreement with the rate found experimentally.

Full text

PDF
5443

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Baker E. N. Structure of azurin from Alcaligenes denitrificans refinement at 1.8 A resolution and comparison of the two crystallographically independent molecules. J Mol Biol. 1988 Oct 20;203(4):1071–1095. doi: 10.1016/0022-2836(88)90129-5. [DOI] [PubMed] [Google Scholar]
  2. Farver O., Pecht I. Long-range intramolecular electron transfer in azurins. Proc Natl Acad Sci U S A. 1989 Sep;86(18):6968–6972. doi: 10.1073/pnas.86.18.6968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Farver O., Skov L. K., van de Kamp M., Canters G. W., Pecht I. The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins. Eur J Biochem. 1992 Dec 1;210(2):399–403. doi: 10.1111/j.1432-1033.1992.tb17434.x. [DOI] [PubMed] [Google Scholar]
  4. Groeneveld C. M., Canters G. W. The pH dependence of the electron self-exchange rate of azurin from Pseudomonas aeruginosa as studied by 1H-NMR. Eur J Biochem. 1985 Dec 16;153(3):559–564. doi: 10.1111/j.1432-1033.1985.tb09337.x. [DOI] [PubMed] [Google Scholar]
  5. Groeneveld C. M., Ouwerling M. C., Erkelens C., Canters G. W. 1H nuclear magnetic resonance study of the protonation behaviour of the histidine residues and the electron self-exchange reaction of azurin from Alcaligenes denitrificans. J Mol Biol. 1988 Mar 5;200(1):189–199. doi: 10.1016/0022-2836(88)90343-9. [DOI] [PubMed] [Google Scholar]
  6. Kaczynski J., Larsson O. Armvenstromboser. Lakartidningen. 1981 Nov 4;78(45):4034–4038. [PubMed] [Google Scholar]
  7. Margalit R., Kostić N. M., Che C. M., Blair D. F., Chiang H. J., Pecht I., Shelton J. B., Shelton J. R., Schroeder W. A., Gray H. B. Preparation and characterization of pentaammineruthenium-(histidine-83)azurin: thermodynamics of intramolecular electron transfer from ruthenium to copper. Proc Natl Acad Sci U S A. 1984 Oct;81(20):6554–6558. doi: 10.1073/pnas.81.20.6554. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Nar H., Messerschmidt A., Huber R., van de Kamp M., Canters G. W. Crystal structure analysis of oxidized Pseudomonas aeruginosa azurin at pH 5.5 and pH 9.0. A pH-induced conformational transition involves a peptide bond flip. J Mol Biol. 1991 Oct 5;221(3):765–772. doi: 10.1016/0022-2836(91)80173-r. [DOI] [PubMed] [Google Scholar]
  9. Nar H., Messerschmidt A., Huber R., van de Kamp M., Canters G. W. X-ray crystal structure of the two site-specific mutants His35Gln and His35Leu of azurin from Pseudomonas aeruginosa. J Mol Biol. 1991 Mar 20;218(2):427–447. doi: 10.1016/0022-2836(91)90723-j. [DOI] [PubMed] [Google Scholar]
  10. Onuchic J. N., Beratan D. N., Winkler J. R., Gray H. B. Pathway analysis of protein electron-transfer reactions. Annu Rev Biophys Biomol Struct. 1992;21:349–377. doi: 10.1146/annurev.bb.21.060192.002025. [DOI] [PubMed] [Google Scholar]
  11. van de Kamp M., Canters G. W., Wijmenga S. S., Lommen A., Hilbers C. W., Nar H., Messerschmidt A., Huber R. Complete sequential 1H and 15N nuclear magnetic resonance assignments and solution secondary structure of the blue copper protein azurin from Pseudomonas aeruginosa. Biochemistry. 1992 Oct 27;31(42):10194–10207. doi: 10.1021/bi00157a006. [DOI] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES