The role of the iron-sulfur cluster in Escherichia coli endonuclease III. A resonance Raman study.
Resonance Raman spectroscopy has been used to investigate the function and properties of the iron-sulfur cluster in Escherichia coli endonuclease III. Resonance Raman spectra in the Fe-S stretching region are indicative of a [4Fe-4S]2+ cluster with complete cysteinyl sulfur coordination, and vibrational assignments are made by analogy with bacterial ferredoxins. Minor changes in the vibrational frequencies of the modes primarily involving Fe-S(Cys) stretching accompany the binding of the inhibitor thymine glycol or an oligonucleotide containing a reduced apyrimidinic site. These changes are consistent with perturbation of the orientation of the ligating cysteinyl residues and rule out the possibility that the [4Fe-4S] cluster is directly involved with substrate or inhibitor binding. It is concluded that a structural role is most likely for the [4Fe-4S] cluster in endonuclease III.
Fu
W
W
Department of Chemistry, University of Georgia, Athens 30602.
O'Handley
S
S
Cunningham
R P
RP
Johnson
M K
MK
D001483:Base Sequence; D001665:Binding Sites; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000378:metabolism*; D013059:Spectrum Analysis, Raman / Q000379:methods; D013379:Substrate Specificity; D013816:Thermodynamics
D029968:Escherichia coli Proteins; D007506:Iron-Sulfur Proteins; D009838:Oligodeoxyribonucleotides; D004706:Endodeoxyribonucleases; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli