1e4b: Difference between revisions

Revision as of 14:38, 2 May 2008

L-FUCULOSE 1-PHOSPHATE ALDOLASE FROM ESCHERICHIA COLI MUTANT N29Q

OverviewOverview

The crystal structures of l-fuculose-1-phosphate aldolase (FucA) with and without a ligated analogue of dihydroxyacetone phosphate (DHAP) and of a number of active center mutants have resulted in a model of the catalytic mechanism. This model has now been confirmed by structural analyses of further mutations at the zinc coordination sphere and at the phosphate site. In addition, these mutants have revealed new aspects of the catalysis: the hydroxyl group of Tyr113' (from a neighboring subunit), which sits just outside the zinc coordination sphere, steers DHAP towards a productive binding mode at the zinc ion; Glu73 contacts zinc in between the two ligand positions intended for the DHAP oxygen atoms and thus avoids blocking of these positions by a tetrahedrally coordinated hydroxy ion; the FucA polypeptide does not assume its minimum energy state but oscillates between two states of elevated energy as demonstrated by a mutant in a minimum energy state. The back and forth motion involves a mobile loop connecting the phosphate site with intersubunit motions and thus with the Brownian motion of the solvent. The phosphate group is bound strongly at a given distance to the zinc ion, which prevents the formation of too tight a DHAP:zinc complex. This observation explains our failure to find mutants that accept phosphate-free substitutes for DHAP. The FucA zinc coordination sphere is compared with that of carbonic anhydrase.

About this StructureAbout this Structure

1E4B is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

Structures of l-fuculose-1-phosphate aldolase mutants outlining motions during catalysis., Joerger AC, Mueller-Dieckmann C, Schulz GE, J Mol Biol. 2000 Nov 3;303(4):531-43. PMID:11054289 Page seeded by OCA on Fri May 2 14:38:41 2008

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OCA

@@ Line 1: / Line 1: @@
 [[Image:1e4b.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1e4b |SIZE=350|CAPTION= <scene name='initialview01'>1e4b</scene>, resolution 1.84&Aring;
+The line below this paragraph, containing "STRUCTURE_1e4b", creates the "Structure Box" on the page.
-|SITE= <scene name='pdbsite=ACT:Active+Center+Definded+By+The+Zn+Ion+And+The+Four+Zn+Coo+...'>ACT</scene> and <scene name='pdbsite=MUT:Mutation+Site'>MUT</scene>
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=BME:BETA-MERCAPTOETHANOL'>BME</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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/L-fuculose-phosphate_aldolase L-fuculose-phosphate aldolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.2.17 4.1.2.17] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1e4b|  PDB=1e4b  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1e4b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1e4b OCA], [http://www.ebi.ac.uk/pdbsum/1e4b PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1e4b RCSB]</span>
-}}
 '''L-FUCULOSE 1-PHOSPHATE ALDOLASE FROM ESCHERICHIA COLI MUTANT N29Q'''
@@ Line 28: / Line 25: @@
 [[Category: Joerger, A C.]]
 [[Category: Schulz, G E.]]
-[[Category: aldolase (class ii)]]
+[[Category: Bacterial l-fucose metabolism]]
-[[Category: bacterial l-fucose metabolism]]
+[[Category: Cleavage of l-fuculose-1-phosphate to dihydroxyacetone phosphate and l-lactaldehyde]]
-[[Category: cleavage of l-fuculose-1-phosphate to dihydroxyacetone phosphate and l-lactaldehyde]]
+[[Category: Mutant structure]]
-[[Category: mutant structure]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 14:38:41 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 19:54:50 2008''