Muonium radical formation in apoferritin and ferritin

Abstract

Using the technique of muon spin relaxation (µSR), repolarisation curves are determined following the deposition of positive muons in samples of apoferritin over the temperature range 50 K to 270 K, and ferritin over the temperature range 15 K to 280 K. Evidence is found for a muonium-substituted species common to both apoferritin and ferritin. In apoferritin at 270 K an estimate for A′, the reduced isotropic muon–electron hyperfine coupling constant, is 168±39 MHz. In ferritin at 280 K the value for A′ is 164±37 MHz.

References

1. G. S. Waldo and E. C. Theil, in Comprehensive Supramolecular Chemistry, ed. J. L. Atwood, J. E. D. Davies, D. D. MacNicol, F. Vögtle and J. M. Lehn, Pergamon, Oxford, 1996, vol. 5, p. 65.
2. P. M. Harrison, G. C. Ford, D. W. Rice, J. M. A. Smith, A. Treffry and J. L. White, in Frontiers in Bioinorganic Chemistry, ed. A. V. Xavier, VCH, Weinheim, 1986, p. 268.
3. M. J. Donlin, R. F. Frey, C. Putnam, J. K. Proctor and J. K. Bashkin, J. Chem. Educ., 1998, 75, 437.
4. B. Webster, Annu. Rep. Prog. Chem., Sect C, 1985, 81, 3.
5. J. H. Brewer and R. Cywinski, in Muon Science: muons in physics, chemistry, and materials, ed. S. L. Lee, S. H. Kilcoyne and R. Cywinski, Institute of Physics Publishing, London, 1999, ch. 1.
6. S. H. Kilcoyne, unpublished work.
7. L. Cristofolini, K. Prassides, K. Vavekis, A. Amato, F. N. Gygax, A. Schenk, S. Gider and D. D. Awschalom, Hyperfine Interact., 1997, 104, 269.
8. K. Nagamine, RIKEN-RAL Muon Facility Report, ed. F. Pratt and K. Ishida, RAL, Chilton, Didcot, Oxon, 1997, 1.
9. E. V. Minaichev, G. G. Myasishcheva, Yu. V. Obukhov, V. S. Roganov, G. I. Savelev and V. G. Firsov, Zh. Eksp. T eor. Fiz., 1970, 58, 1586; Sov. Phys. JETP (Engl. Transl.), 1970, 31, 849.
10. S. H. Bell, M. P. Weir, D. P. E. Dickson, J. F. Gibson, G. A. Sharp and T. J. Peters, Biochim. Biophys. Acta, 1984, 787, 227.
11. S. H. Kilcoyne and R. Cywinski, J. Magn. Magn. Mater., 1995, 140–144, 1466.
12. D. Yu, P. W. Percival, J. C. Brodovitch, S. K. Leung, R. F. Kiefl, K. Venkateswaram and S. F. J. Cox, Chem. Phys., 1990, 142, 229.