Abstract
The binding of horse heart mitochondrial cytochrome c to isolated reaction centers from Rhodopseudomonas sphaeroides is described. The kinetics of photooxidation of cytochrome c following a short actinic flash is compared to the expected binding state of the cytochrome at various concentrations and at different ionic strengths. At low ionic strength a very tight binding site (KD ≦ 10-8 M) is apparent which is nonfunctional with respect to electron donation to the bound reaction center. This tightly bound cytochrome can react with another reaction center in a diffusion limited, second order process. A weaker binding site (KD ≃ 0.3 • 10−6 M) is also observed which is associated with rapid, first order electron transfer from cytochrome to reaction center. Both binding processes are weakened in the presence of salt and there is no detectable binding in 100 mM NaCl. Under such conditions cytochrome oxidation is entirely a diffusional, second order process. However, analysis of the flash intensity dependence of the extent of cytochrome oxidation, by the method of van Grondelle (van Grondelle, R. (1978) Ph.D. Thesis, State University, Leiden) indicated that the cytochrome was not freely mobile even in 100 mM NaCl, at least in the sense that reduced cytochrome only slowly dissociates from unactivated reaction centers. An overall kinetic/equilibrium scheme for cytochrome c binding and photooxidation by reaction centers is presented. This is very similar to that described earlier for cytochrome c2 (Overfield, R.E., Wraight, C.A. and DeVault, D. (1979) FEBS Lett. 105, 137–142), but the tight binding site and associated diffusion controlled oxidation is unique to cytochrome c.
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References
Bashford CL, Prince RC, Takamiya K and Dutton PL (1979) Biochim Biophys Acta 545, 223–235
Brunner J, Skabal P and Hauser H (1976) Biochim Biophys Acta 455, 322–331
Dutton PL, Petty KM, Bonner HS and Morse SD (1975) Biochim Biophys Acta 389, 536–556
Eigen M (1974) in Quantum Statistical Mechanisms in the Natural Sciences, Plenum Press, New York
Ferguson-Miller S, Brautigan DL and Margoliash E (1978) J Biol Chem 253, 149–159
Ke B, Chaney TH and Reed D (1970) Biochim Biophys Acta 216, 373–383
Matsuura K and Nishimura M (1985) Biochim Biophys Acta In press
Overfield RE and Wraight CA (1980) Biochemistry 19, 3322–3327
Overfield RE, Wraight CA and DeVault D (1979) Febs Lett 105, 137–142
Pachence JM, Dutton PL and Blasie JK (1983) Biochim Biophys Acta 724, 6–19
Prince RC, Bashford CL, Takamiya K, van den Berg WH and Dutton PL (1978) J Biol Chem 253, 4137–4142
Prince RC, Cogdell RJ and Crofts AR (1974) Biochim Biophys Acta 347, 1–13
Rickle G and Cusanovich M (1979) Arch Biochem Biophys 197, 589–598
Rosen D, Okamura MY and Feher G (1980) Biochemistry 19, 5687–5692
Singleton WS, Gray MS, Brown ML and White JL (1965) J Amer Oil Chemists Soc 42, 53–56
Snozzi M and Crofts AR (1985) Biochim Biophys Acta In press
Van Grondelle R, Duysens LNM and van der Wal HN (1976) Biochim Biophys Acta 449, 169–187
Van Grondelle R, Duysens LNM, van der Wel JA and van der Wal HN (1977) Biochim Biophys Acta 461, 188–201
Van Grondelle R (1978) Ph.D. Thesis, State University, Leiden
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© 1986 Martinus Nijhoff/Dr. W. Junk Publishers, Dordrecht
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Overfield, R.E., Wraight, C.A. (1986). Photooxidation of mitochondrial cytochrome c by isolated bacterial reaction centers: Evidence for tight-binding and diffusional pathways. In: Amesz, J., Hoff, A.J., Van Gorkum, H.J. (eds) Current topics in photosynthesis. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-4412-1_17
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DOI: https://doi.org/10.1007/978-94-009-4412-1_17
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-8463-5
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