Source:http://linkedlifedata.com/resource/pubmed/id/19711960
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
39
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pubmed:dateCreated |
2009-9-29
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pubmed:abstractText |
Pyruvate formate-lyase activating enzyme (PFL-AE) catalyzes the generation of a catalytically essential glycyl radical on pyruvate formate-lyase (PFL). Purified PFL-AE contains an oxygen-sensitive, labile [4Fe-4S] cluster that undergoes cluster interconversions in vitro, with only the [4Fe-4S](+) cluster state being catalytically active. Such cluster interconversions could play a role in regulating the activity of PFL-AE, and thus of PFL, in response to oxygen levels in vivo. Here we report a Mossbauer investigation on whole cells overexpressing PFL-AE following incubation under aerobic and/or anaerobic conditions and provide evidence that PFL-AE undergoes cluster interconversions in vivo. After 2 h aerobic induction of PFL-AE expression, approximately 44% of the total iron is present in [4Fe-4S](2+) clusters, 6% in [2Fe-2S](2+) clusters, and the remainder as noncluster Fe(III) (29%) and Fe(II) (21%) species. Subsequent anaerobic incubation of the culture results in approximately 75% of the total iron being present as [4Fe-4S](2+) clusters, with no detectable [2Fe-2S](2+). Ensuing aerobic incubation of the culture converts the iron species nearly back to the original composition (42% [4Fe-4S](2+), 10% [2Fe-2S](2+), 19% Fe(III), and 29% Fe(II)). The results provide evidence for changes in cluster composition of PFL-AE in response to the redox state of the cell. Furthermore, the Mossbauer spectra reveal that the [4Fe-4S](2+) cluster of PFL-AE in whole cells contains a valence-localized Fe(III)Fe(II) pair which has not been previously observed in the purified enzyme. Addition of certain small molecules containing adenosyl moieties, including 5'-deoxyadenosine, AMP, ADP, and methylthioadenosine, to purified PFL-AE reproduces the valence-localized state of the [4Fe-4S](2+) cluster. It is speculated that the [4Fe-4S](2+) cluster of PFL-AE in whole cells may be coordinated by a small molecule, probably AMP, and that such coordination may protect this labile cluster from oxidative damage.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Enzymes,
http://linkedlifedata.com/resource/pubmed/chemical/Escherichia coli Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Ferric Compounds,
http://linkedlifedata.com/resource/pubmed/chemical/Ferrous Compounds,
http://linkedlifedata.com/resource/pubmed/chemical/Iron-Sulfur Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/pyruvate formate-lyase activating...
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
1520-4995
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pubmed:author | |
pubmed:issnType |
Electronic
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pubmed:day |
6
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pubmed:volume |
48
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
9234-41
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pubmed:meshHeading |
pubmed-meshheading:19711960-Electrons,
pubmed-meshheading:19711960-Enzyme Activation,
pubmed-meshheading:19711960-Enzymes,
pubmed-meshheading:19711960-Escherichia coli,
pubmed-meshheading:19711960-Escherichia coli Proteins,
pubmed-meshheading:19711960-Ferric Compounds,
pubmed-meshheading:19711960-Ferrous Compounds,
pubmed-meshheading:19711960-Gene Expression Regulation, Bacterial,
pubmed-meshheading:19711960-Iron-Sulfur Proteins,
pubmed-meshheading:19711960-Spectroscopy, Mossbauer
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pubmed:year |
2009
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pubmed:articleTitle |
The iron-sulfur cluster of pyruvate formate-lyase activating enzyme in whole cells: cluster interconversion and a valence-localized [4Fe-4S]2+ state.
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pubmed:affiliation |
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, N.I.H., Extramural
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