1mbb
From Proteopedia
(New page: 200px<br /><applet load="1mbb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mbb, resolution 2.30Å" /> '''OXIDOREDUCTASE'''<br...) |
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| - | [[Image:1mbb.gif|left|200px]]<br /><applet load="1mbb" size=" | + | [[Image:1mbb.gif|left|200px]]<br /><applet load="1mbb" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1mbb, resolution 2.30Å" /> | caption="1mbb, resolution 2.30Å" /> | ||
'''OXIDOREDUCTASE'''<br /> | '''OXIDOREDUCTASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | UDP-N-acetylenolpyruvylglucosamine reductase (MurB), a peptidoglycan | + | UDP-N-acetylenolpyruvylglucosamine reductase (MurB), a peptidoglycan biosynthetic enzyme from Escherichia coli, reduces both (E)- and (Z)-isomers of enolbutyryl-UDP-GlcNAc, C4 analogs of the physiological C3 enolpyruvyl substrate, to UDP-methyl-N-acetylmuramic acid in the presence of NADPH. The X-ray crystal structure of the (E)-enolbutyryl-UDP-GlcNAc-MurB complex is similar to that of the enolpyruvyl-UDP-GlcNAc-MurB complex. In both structures the groups thought to be involved in hydride transfer to C3 and protonation at C2 of the enol ether substrate are arranged anti relative to the enol double bond. The stereochemical outcome of reduction of (E)-enolbutyryl-UDP-GlcNAc by NADPD in D2O is thus predicted to yield a (2R,3R)-dideuterio product. This was validated by conversion of the 2,3-dideuterio-UDP-methyl-N-acetylmuramic acid product to 2,3-dideuterio-2-hydroxybutyrate, which was shown to be (2R) by enzymatic analysis and (3R) by NMR comparison to authentic (2R,3R)- and (2R,3S)-2,3-dideuterio-2-hydroxybutyrate. Remarkably, the (E)-enolbutyryl-UDP-GlcNAc was found to partition between reduction to UDP-methyl-N-acetylmuramic and isomerization to the (Z)-substrate isomer in the MurB active site, indicative of a C2 carbanion/enol species that is sufficiently long-lived to rotate around the C2-C3 single bond during catalysis. |
==About this Structure== | ==About this Structure== | ||
| - | 1MBB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with EEB and FAD as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/UDP-N-acetylmuramate_dehydrogenase UDP-N-acetylmuramate dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.158 1.1.1.158] Full crystallographic information is available from [http:// | + | 1MBB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=EEB:'>EEB</scene> and <scene name='pdbligand=FAD:'>FAD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/UDP-N-acetylmuramate_dehydrogenase UDP-N-acetylmuramate dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.158 1.1.1.158] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MBB OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: UDP-N-acetylmuramate dehydrogenase]] | [[Category: UDP-N-acetylmuramate dehydrogenase]] | ||
| - | [[Category: Benson, T | + | [[Category: Benson, T E.]] |
| - | [[Category: Hogle, J | + | [[Category: Hogle, J M.]] |
| - | [[Category: Lees, W | + | [[Category: Lees, W J.]] |
| - | [[Category: Walsh, C | + | [[Category: Walsh, C T.]] |
[[Category: EEB]] | [[Category: EEB]] | ||
[[Category: FAD]] | [[Category: FAD]] | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:53:28 2008'' |
Revision as of 11:53, 21 February 2008
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OXIDOREDUCTASE
Overview
UDP-N-acetylenolpyruvylglucosamine reductase (MurB), a peptidoglycan biosynthetic enzyme from Escherichia coli, reduces both (E)- and (Z)-isomers of enolbutyryl-UDP-GlcNAc, C4 analogs of the physiological C3 enolpyruvyl substrate, to UDP-methyl-N-acetylmuramic acid in the presence of NADPH. The X-ray crystal structure of the (E)-enolbutyryl-UDP-GlcNAc-MurB complex is similar to that of the enolpyruvyl-UDP-GlcNAc-MurB complex. In both structures the groups thought to be involved in hydride transfer to C3 and protonation at C2 of the enol ether substrate are arranged anti relative to the enol double bond. The stereochemical outcome of reduction of (E)-enolbutyryl-UDP-GlcNAc by NADPD in D2O is thus predicted to yield a (2R,3R)-dideuterio product. This was validated by conversion of the 2,3-dideuterio-UDP-methyl-N-acetylmuramic acid product to 2,3-dideuterio-2-hydroxybutyrate, which was shown to be (2R) by enzymatic analysis and (3R) by NMR comparison to authentic (2R,3R)- and (2R,3S)-2,3-dideuterio-2-hydroxybutyrate. Remarkably, the (E)-enolbutyryl-UDP-GlcNAc was found to partition between reduction to UDP-methyl-N-acetylmuramic and isomerization to the (Z)-substrate isomer in the MurB active site, indicative of a C2 carbanion/enol species that is sufficiently long-lived to rotate around the C2-C3 single bond during catalysis.
About this Structure
1MBB is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as UDP-N-acetylmuramate dehydrogenase, with EC number 1.1.1.158 Full crystallographic information is available from OCA.
Reference
(E)-enolbutyryl-UDP-N-acetylglucosamine as a mechanistic probe of UDP-N-acetylenolpyruvylglucosamine reductase (MurB)., Lees WJ, Benson TE, Hogle JM, Walsh CT, Biochemistry. 1996 Feb 6;35(5):1342-51. PMID:8634262
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