1g94: Difference between revisions

Revision as of 17:18, 2 May 2008

CRYSTAL STRUCTURE ANALYSIS OF THE TERNARY COMPLEX BETWEEN PSYCHROPHILIC ALPHA AMYLASE FROM PSEUDOALTEROMONAS HALOPLANCTIS IN COMPLEX WITH A HEPTA-SACCHARIDE AND A TRIS MOLECULE

OverviewOverview

The psychrophilic Pseudoalteromonas haloplanctis alpha-amylase is shown to form ternary complexes with two alpha-amylase inhibitors present in the active site region, namely, a molecule of Tris and a trisaccharide inhibitor or heptasaccharide inhibitor, respectively. The crystal structures of these complexes have been determined by X-ray crystallography to 1.80 and 1.74 A resolution, respectively. In both cases, the prebound inhibitor Tris is expelled from the active site by the incoming oligosaccharide inhibitor substrate analogue, but stays linked to it, forming well-defined ternary complexes with the enzyme. These results illustrate competition in the crystalline state between two inhibitors, an oligosaccharide substrate analogue and a Tris molecule, bound at the same time in the active site region. Taken together, these structures show that the enzyme performs transglycosylation in the complex with the pseudotetrasaccharide acarbose (confirmed by a mutant structure), leading to a well-defined heptasaccharide, considered as a more potent inhibitor. Furthermore, the substrate-induced ordering of water molecules within a channel highlights a possible pathway used for hydrolysis of starch and related poly- and oligosaccharides.

About this StructureAbout this Structure

1G94 is a Single protein structure of sequence from Pseudoalteromonas haloplanktis. Full crystallographic information is available from OCA.

ReferenceReference

Crystallographic evidence of a transglycosylation reaction: ternary complexes of a psychrophilic alpha-amylase., Aghajari N, Roth M, Haser R, Biochemistry. 2002 Apr 2;41(13):4273-80. PMID:11914073 Page seeded by OCA on Fri May 2 17:17:58 2008

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OCA

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 [[Image:1g94.jpg|left|200px]]
- {{Structure
+<!--
-|PDB= 1g94 |SIZE=350|CAPTION= <scene name='initialview01'>1g94</scene>, resolution 1.74&Aring;
+The line below this paragraph, containing "STRUCTURE_1g94", 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=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=DAF:1,4-DEOXY-4-((5-HYDROXYMETHYL-2,3,4-TRIHYDROXYCYCLOHEX-5-ENYL)AMINO)FRUCTOSE'>DAF</scene>, <scene name='pdbligand=GLC:GLUCOSE'>GLC</scene>, <scene name='pdbligand=TRS:2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL'>TRS</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/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1g94|  PDB=1g94  |  SCENE=  }}
-|RELATEDENTRY=[[1aqh|1AQH]], [[1aqm|1AQM]], [[1b0i|1b0i]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1g94 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1g94 OCA], [http://www.ebi.ac.uk/pdbsum/1g94 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1g94 RCSB]</span>
-}}
 '''CRYSTAL STRUCTURE ANALYSIS OF THE TERNARY COMPLEX BETWEEN PSYCHROPHILIC ALPHA AMYLASE FROM PSEUDOALTEROMONAS HALOPLANCTIS IN COMPLEX WITH A HEPTA-SACCHARIDE AND A TRIS MOLECULE'''
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 [[Category: Roth, M.]]
 [[Category: 3 domain structure]]
-[[Category: beta-alpha-8-barrel]]
+[[Category: Beta-alpha-8-barrel]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 17:17:58 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 20:39:26 2008''