1qhm: Difference between revisions
New page: left|200px<br /><applet load="1qhm" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qhm, resolution 2.80Å" /> '''ESCHERICHIA COLI PYR... |
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[[Image:1qhm.jpg|left|200px]]<br /><applet load="1qhm" size=" | [[Image:1qhm.jpg|left|200px]]<br /><applet load="1qhm" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1qhm, resolution 2.80Å" /> | caption="1qhm, resolution 2.80Å" /> | ||
'''ESCHERICHIA COLI PYRUVATE FORMATE LYASE LARGE DOMAIN'''<br /> | '''ESCHERICHIA COLI PYRUVATE FORMATE LYASE LARGE DOMAIN'''<br /> | ||
==Overview== | ==Overview== | ||
BACKGROUND: Pyruvate formate lyase (PFL) catalyses a key step in | BACKGROUND: Pyruvate formate lyase (PFL) catalyses a key step in Escherichia coli anaerobic glycolysis by converting pyruvate and CoA to formate and acetylCoA. The PFL mechanism involves an unusual radical cleavage of pyruvate, involving an essential C alpha radical of Gly734 and two cysteine residues, Cys418 and Cys419, which may form thiyl radicals required for catalysis. We undertook this study to understand the structural basis for catalysis. RESULTS: The first structure of a fragment of PFL (residues 1-624) at 2.8 A resolution shows an unusual barrel-like structure, with a catalytic beta finger carrying Cys418 and Cys419 inserted into the centre of the barrel. Several residues near the active-site cysteines can be ascribed roles in the catalytic mechanism: Arg176 and Arg435 are positioned near Cys419 and may bind pyruvate/formate and Trp333 partially buries Cys418. Both cysteine residues are accessible to each other owing to their cis relationship at the tip of the beta finger. Finally, two clefts that may serve as binding sites for CoA and pyruvate have been identified. CONCLUSIONS: PFL has striking structural homology to the aerobic ribonucleotide reductase (RNR): the superposition of PFL and RNR includes eight of the ten strands in the unusual RNR alpha/beta barrel as well as the beta finger, which carries key catalytic residues in both enzymes. This provides the first structural proof that RNRs and PFLs are related by divergent evolution from a common ancestor. | ||
==About this Structure== | ==About this Structure== | ||
1QHM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Formate_C-acetyltransferase Formate C-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.54 2.3.1.54] Full crystallographic information is available from [http:// | 1QHM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Formate_C-acetyltransferase Formate C-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.54 2.3.1.54] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QHM OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Goldman, A.]] | [[Category: Goldman, A.]] | ||
[[Category: Kozarich, J | [[Category: Kozarich, J W.]] | ||
[[Category: Leppanen, V | [[Category: Leppanen, V M.]] | ||
[[Category: Merckel, M | [[Category: Merckel, M C.]] | ||
[[Category: Ollis, D | [[Category: Ollis, D L.]] | ||
[[Category: Wong, K | [[Category: Wong, K K.]] | ||
[[Category: anaerobic]] | [[Category: anaerobic]] | ||
[[Category: enzyme mechanism]] | [[Category: enzyme mechanism]] | ||
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[[Category: x-ray crystallography]] | [[Category: x-ray crystallography]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:39:40 2008'' | ||
Revision as of 15:39, 21 February 2008
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ESCHERICHIA COLI PYRUVATE FORMATE LYASE LARGE DOMAIN
OverviewOverview
BACKGROUND: Pyruvate formate lyase (PFL) catalyses a key step in Escherichia coli anaerobic glycolysis by converting pyruvate and CoA to formate and acetylCoA. The PFL mechanism involves an unusual radical cleavage of pyruvate, involving an essential C alpha radical of Gly734 and two cysteine residues, Cys418 and Cys419, which may form thiyl radicals required for catalysis. We undertook this study to understand the structural basis for catalysis. RESULTS: The first structure of a fragment of PFL (residues 1-624) at 2.8 A resolution shows an unusual barrel-like structure, with a catalytic beta finger carrying Cys418 and Cys419 inserted into the centre of the barrel. Several residues near the active-site cysteines can be ascribed roles in the catalytic mechanism: Arg176 and Arg435 are positioned near Cys419 and may bind pyruvate/formate and Trp333 partially buries Cys418. Both cysteine residues are accessible to each other owing to their cis relationship at the tip of the beta finger. Finally, two clefts that may serve as binding sites for CoA and pyruvate have been identified. CONCLUSIONS: PFL has striking structural homology to the aerobic ribonucleotide reductase (RNR): the superposition of PFL and RNR includes eight of the ten strands in the unusual RNR alpha/beta barrel as well as the beta finger, which carries key catalytic residues in both enzymes. This provides the first structural proof that RNRs and PFLs are related by divergent evolution from a common ancestor.
About this StructureAbout this Structure
1QHM is a Single protein structure of sequence from Escherichia coli. Active as Formate C-acetyltransferase, with EC number 2.3.1.54 Full crystallographic information is available from OCA.
ReferenceReference
Pyruvate formate lyase is structurally homologous to type I ribonucleotide reductase., Leppanen VM, Merckel MC, Ollis DL, Wong KK, Kozarich JW, Goldman A, Structure. 1999 Jul 15;7(7):733-44. PMID:10425676
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