1mor: Difference between revisions

Revision as of 01:31, 3 May 2008

ISOMERASE DOMAIN OF GLUCOSAMINE 6-PHOSPHATE SYNTHASE COMPLEXED WITH GLUCOSE 6-PHOSPHATE

OverviewOverview

BACKGROUND: Glucosamine 6-phosphate synthase (GlmS) catalyses the first step in hexosamine metabolism, converting fructose-6P (6 phosphate) into glucosamine-6P using glutamine as a nitrogen source. GlmS is a bienzyme complex consisting of two domains that catalyse glutamine hydrolysis and sugar-phosphate isomerisation, respectively. Knowledge of the three-dimensional structure of GlmS is essential for understanding the general principles of catalysis by ketol isomerases and the mechanism of nitrogen transfer in glutamine amidotransferases. RESULTS: The crystal structure of the isomerase domain of the Escherichia coli GlmS with the reaction product, glucosamine-6P, has been determined at 1.57 A resolution. It is comprised of two topologically identical subdomains, each of which is dominated by a nucleotide-binding motif of a flavodoxin type. The catalytic site is assembled by dimerisation of the protein. CONCLUSIONS: The isomerase active site of GlmS seems to be the result of evolution through gene duplication and subsequent dimerisation. Isomerisation of fructose-6P is likely to involve the formation of a Schiff base with Lys603 of the enzyme, the ring-opening step catalysed by His504, and the proton transfer from C1 to C2 of the substrate effected by Glu488. The highly conserved C-terminal fragment of the chain may play a key role in substrate binding, catalysis and communication with the glutaminase domain. The corresponding sequence pattern DXPXXLAK[SC]VT (in single-letter amino-acid code, where X is any amino acid and letters in brackets indicate that either serine or cysteine may take this position) may be considered as a fingerprint of GlmS.

About this StructureAbout this Structure

1MOR is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

Involvement of the C terminus in intramolecular nitrogen channeling in glucosamine 6-phosphate synthase: evidence from a 1.6 A crystal structure of the isomerase domain., Teplyakov A, Obmolova G, Badet-Denisot MA, Badet B, Polikarpov I, Structure. 1998 Aug 15;6(8):1047-55. PMID:9739095 Page seeded by OCA on Sat May 3 01:31:49 2008

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OCA

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 [[Image:1mor.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1mor |SIZE=350|CAPTION= <scene name='initialview01'>1mor</scene>, resolution 1.90&Aring;
+The line below this paragraph, containing "STRUCTURE_1mor", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=G6P:ALPHA-D-GLUCOSE-6-PHOSPHATE'>G6P</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Glutamine--fructose-6-phosphate_transaminase_(isomerizing) Glutamine--fructose-6-phosphate transaminase (isomerizing)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.16 2.6.1.16] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1mor|  PDB=1mor  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1mor FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mor OCA], [http://www.ebi.ac.uk/pdbsum/1mor PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1mor RCSB]</span>
-}}
 '''ISOMERASE DOMAIN OF GLUCOSAMINE 6-PHOSPHATE SYNTHASE COMPLEXED WITH GLUCOSE 6-PHOSPHATE'''
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 Involvement of the C terminus in intramolecular nitrogen channeling in glucosamine 6-phosphate synthase: evidence from a 1.6 A crystal structure of the isomerase domain., Teplyakov A, Obmolova G, Badet-Denisot MA, Badet B, Polikarpov I, Structure. 1998 Aug 15;6(8):1047-55. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/9739095 9739095]
 [[Category: Escherichia coli]]
-[[Category: Glutamine--fructose-6-phosphate transaminase (isomerizing)]]
 [[Category: Single protein]]
 [[Category: Teplyakov, A.]]
-[[Category: glutamine amidotransferase]]
+[[Category: Glutamine amidotransferase]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 01:31:49 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 22:18:58 2008''