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Volumn 127, Issue 19, 2005, Pages 6977-6989

Electron transfer and catalytic control by the iron-sulfur clusters in a respiratory enzyme, E. coli fumarate reductase

Author keywords

[No Author keywords available]

Indexed keywords

CATALYSIS; ELECTRONS; ESCHERICHIA COLI; MUTAGENESIS; PROTEINS; SULFUR;

EID: 18744363629     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja043404q     Document Type: Article
Times cited : (85)

References (53)
  • 15
    • 0025783505 scopus 로고
    • It was suggested that the microscopic reduction potential of the [4Fe-4S] cluster is not as low as the macroscopic value, due to anti-cooperative interactions between the clusters (Salerno, J. C. Biochem. Soc. Trans. 1991, 19, 599-605)
    • (1991) Biochem. Soc. Trans. , vol.19 , pp. 599-605
    • Salerno, J.C.1
  • 16
    • 0025225686 scopus 로고
    • . However, studies on mutants in which the potentials of the [2Fe-2S] and [3Fe-4S] clusters were altered showed that the intrinsic midpoint potential of the [4Fe-4S] cluster is still below -240 mV, which should provide a significant barrier to ET in either direction (ref 41 and Werth, M. T.; Cecchini, G.; Manodori, A.; Ackrell, B. A. C.; Schroder, I.; Gunsalus, R. P.; Johnson, M. K. Proc. Natl. Acad. Sci. U.S.A. 1990, 87, 8965-8969).
    • (1990) Proc. Natl. Acad. Sci. U.S.A. , vol.87 , pp. 8965-8969
    • Werth, M.T.1    Cecchini, G.2    Manodori, A.3    Ackrell, B.A.C.4    Schroder, I.5    Gunsalus, R.P.6    Johnson, M.K.7
  • 26
    • 18744416184 scopus 로고    scopus 로고
    • note
    • -1, and so PIPES was used for these experiments instead. This effect was not observed in previous studies (see ref 22) and may have been caused by a contaminant.
  • 32
    • 18744405919 scopus 로고    scopus 로고
    • note
    • Since deconvolution assumes equilibrium conditions (and thus slow scan rates), the ET rates to the [3Fe-4S] and [2Fe-2S] clusters cannot be measured in this way.
  • 37
    • 18744399758 scopus 로고    scopus 로고
    • note
    • -1.
  • 40
    • 18744412028 scopus 로고    scopus 로고
    • The reduction potential varies slightly with buffer concentration; see Materials and Methods.
    • Materials and Methods
  • 41
    • 18744377888 scopus 로고    scopus 로고
    • note
    • 19 However, this process is unlikely to be useful in a one-electron relay.
  • 47
    • 0142231009 scopus 로고    scopus 로고
    • This equation (described in ref 7 and in: Page, C. C.; Moser, C. C.; Dutton, P. L. Curr. Opin. Chem. Biol. 2003, 7, 551-556) describes the ET rate constant within proteins in terms of the distance between centers, the packing density of the protein, the change in free energy, and the reorganization energy. The calculation included a standard value for the protein packing density as 0.75, reorganization energy of the Fe-S clusters as 0.7 eV, and the edge-edge distances from the WT crystal structure. The ET rate for each mutant was based on the step from the [3Fe-4S] to the [4Fe-4S] cluster since this is the most energetically unfavorable step and would most likely be rate-determining if energetics were to control the inherent kinetics of electron flow along the relay.
    • (2003) Curr. Opin. Chem. Biol. , vol.7 , pp. 551-556
    • Page, C.C.1    Moser, C.C.2    Dutton, P.L.3
  • 49
    • 0025328799 scopus 로고
    • Menaquinone is reported to have a reduction potential of -74 mV at pH 7 for the two-electron reaction (Wissenbach, U.; Kröger, G.; Unden, G. Arch. Microbiol. 1990, 154, 60-66).
    • (1990) Arch. Microbiol. , vol.154 , pp. 60-66
    • Wissenbach, U.1    Kröger, G.2    Unden, G.3
  • 50
    • 0017254222 scopus 로고
    • For DMN (2,3-dimethyl-1,4-naphthoquinone), a reduction potential of -240 mV is reported for the one-electron reduction of quinone to radical (Ilan, Y. A.; Czapski, G.; Meisel, D. Biochim. Biophys. Acta 1976, 430, 209-224).
    • (1976) Biochim. Biophys. Acta , vol.430 , pp. 209-224
    • Ilan, Y.A.1    Czapski, G.2    Meisel, D.3
  • 51
    • 18744385135 scopus 로고    scopus 로고
    • note
    • These OAA release rates were measured in the presence of chloride, which (like other anions) has been shown to bind to the active site. The presence of chloride in these experiments is responsible for the higher release rates and weaker binding reported here compared to those measured previously (see ref 13).
  • 53
    • 18744364082 scopus 로고    scopus 로고
    • note
    • It is known also that malate can be oxidized to OAA by SQR (ref 38), thus enhanced release of OAA by a very slow catalytic reduction process, which might somehow be enhanced by the delivery of two electrons, also remains a possibility. Although OAA reduction could not be detected with PFV, more sensitive gas chromatography analysis of the products after bulk catalysis may provide more evidence for this possibility.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.