TY - JOUR
T1 - Interaction of iron-sulfur flavoprotein with oxygen and hydrogen peroxide
AU - Cruz, Francisco
AU - Ferry, James G.
N1 - Funding Information:
This work was funded by Department of Energy grant DE-FG02-95ER20198 to J.G.F., and the Penn State Astrobiology Research Center (through the National Astrobiology Institute). We are deeply indebted to J. Martin Bollinger for many valuable discussions and use of his stopped-flow spectrophotometer.
PY - 2006/6
Y1 - 2006/6
N2 - The dimeric iron-sulfur flavoprotein (Isf) from Methanosarcina thermophila contains one 4Fe-4S center and one FMN per monomer, and is the prototype of a family widely distributed among strictly anaerobic prokaryotes. Although Isf is able to oxidize ferredoxin, the physiological electron acceptor is unknown; thus, the ability of Isf to reduce O2 and H2O2 was investigated. The product of O2 or H2O2 reduction by Isf was determined to be water. The kinetic parameters of the oxidative half-reactions with O2 and H2O2 as electron acceptors were consistent with a role for Isf in combating oxidative stress. Isf depleted of the 4Fe-4S cluster was unable to oxidize ferredoxin and reduce the FMN cofactor, supporting a role for the cluster in transfer of electrons from ferredoxin to the cofactor. The implications of these properties on the possible function and mechanism of Isf are discussed.
AB - The dimeric iron-sulfur flavoprotein (Isf) from Methanosarcina thermophila contains one 4Fe-4S center and one FMN per monomer, and is the prototype of a family widely distributed among strictly anaerobic prokaryotes. Although Isf is able to oxidize ferredoxin, the physiological electron acceptor is unknown; thus, the ability of Isf to reduce O2 and H2O2 was investigated. The product of O2 or H2O2 reduction by Isf was determined to be water. The kinetic parameters of the oxidative half-reactions with O2 and H2O2 as electron acceptors were consistent with a role for Isf in combating oxidative stress. Isf depleted of the 4Fe-4S cluster was unable to oxidize ferredoxin and reduce the FMN cofactor, supporting a role for the cluster in transfer of electrons from ferredoxin to the cofactor. The implications of these properties on the possible function and mechanism of Isf are discussed.
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U2 - 10.1016/j.bbagen.2006.02.016
DO - 10.1016/j.bbagen.2006.02.016
M3 - Article
C2 - 16624489
AN - SCOPUS:33744541766
SN - 0006-3002
VL - 1760
SP - 858
EP - 864
JO - Biochimica et Biophysica Acta - General Subjects
JF - Biochimica et Biophysica Acta - General Subjects
IS - 6
ER -