Dissimilatory sulfite reductase revisited. The desulfoviridin molecule does contain 20 iron ions, extensively demetallated sirohaem, and an S = 9/2 iron-sulfur cluster.
Assimilatory sulfite reductase contains a sirohaem that is very weakly coupled to a [4Fe-4S] cubane, i.e. five iron atoms in total. Dissimilatory sulfite reductase is a complex system with 20 Fe atoms/alpha 2 beta 2 gamma 2 hexamer. A recent revision of the purification procedure for the Desulfovibrio vulgaris dissimilatory enzyme has afforded a preparation of only 10 Fe atoms hexamer, this has led to the convulsion that the topology of prosthetic groups parallels that of the assimilatory system [Wolfe, B. M., Lui, S. M. & Cowan, J. A. (1994) Eur. J. Biochem. 223, 79-89]. The new purification procedure has been reproduced but the claimed molecular properties are not reproducible. The highly purified, active desulfoviridin contains 20, not 10, Fe atoms/molecule: the sirohaem is extensively dematallated, not metallated; and the S = 9/2 iron-sulfur cluster is present, not absent.
Marritt
S J
SJ
Department of Biochemistry, Wageningen Agricultural University, The Netherlands.
Hagen
W F
WF
D016969:Desulfovibrio vulgaris / Q000737:chemistry / Q000201:enzymology; D004578:Electron Spin Resonance Spectroscopy; D050885:Hydrogensulfite Reductase; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013455:Sulfur / Q000737:chemistry / Q000378:metabolism
D013455:Sulfur; D007501:Iron; D050862:Oxidoreductases Acting on Sulfur Group Donors; D050885:Hydrogensulfite Reductase