These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Characterization of the Fe-S cluster in aconitase using low temperature magnetic circular dichroism spectroscopy.
    Author: Johnson MK, Thomson AJ, Richards AJ, Peterson J, Robinson AE, Ramsay RR, Singer TP.
    Journal: J Biol Chem; 1984 Feb 25; 259(4):2274-82. PubMed ID: 6698964.
    Abstract:
    Beef heart aconitase has been studied by low temperature magnetic circular dichroism (MCD) spectroscopy in the wavelength region 300 to 1900 nm. Together with parallel electron paramagnetic resonance and activity measurements, these data enable correlations between Fe-S cluster-type and enzymic activity in aconitase. In samples not exposed to extraneous Fe, the Fe-S cluster in aconitase exhibits the characteristic properties of a 3Fe center in both the as isolated and dithionite-reduced states. On the basis of the detailed form of the low temperature MCD spectra, three types of 3Fe center can be distinguished in biological samples. These are typified by the 3Fe centers in aconitase, Desulfovibrio gigas FdII, and Azotobacter crooccocum Fd. In aconitase, maximal enzymic activity is found to be associated with the build-up of [4Fe-4S]2+ clusters in good agreement with the Mössbauer studies of Kent et al. (Kent, T. A., Dreyer, J. L., Kennedy, M. C., Huynh, B. H., Emptage, M. H., Beinert, H., and Münck, E. (1982) Proc. Natl. Acad. Sci. U. S. A. 79, 1096-1100). However, significant catalytic activity (approximately 60%) was obtained by reduction of the 3Fe center with dithionite in the absence of added Fe. The form and intensity of the resultant MCD spectrum are consistent with the majority of the Fe being in the form of reduced 3Fe clusters. The possibility that a reduced 3Fe cluster is capable of promoting partial catalytic activity in aconitase is discussed in light of these results.
    [Abstract] [Full Text] [Related] [New Search]