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The iron–sulfur cluster in the l ‐serine dehydratase TdcG from Escherichia coli is required for enzyme activity
Author(s) -
Burman Julia D.,
Harris Roger L.,
Hauton Katherine A.,
Lawson David M.,
Sawers R.Gary
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2004.09.058
Subject(s) - dehydratase , escherichia coli , chemistry , enzyme , biochemistry , serine , cluster (spacecraft) , iron–sulfur cluster , rhodanese , gene , computer science , programming language
The anaerobically inducible l ‐serine dehydratase, TdcG, from Escherichia coli was characterized. Based on UV–visible spectroscopy, iron and labile sulfide analyses, the homodimeric enzyme is proposed to have two oxygen‐labile [4Fe–4S] 2+ clusters. Anaerobically isolated dimeric TdcG had a k cat of 544 s −1 and an apparent K M for l ‐serine of 4.8 mM. l ‐threonine did not act as a substrate for the enzyme. Exposure of the active enzyme to air resulted in disappearance of the broad absorption band at 400–420 nm, indicating a loss of the [4Fe–4S] 2+ cluster. A concomitant loss of dehydratase activity was demonstrated, indicating that integrity of the [4Fe–4S] 2+ cluster is essential for enzyme activity.