1ppy: Difference between revisions

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[[Image:1ppy.gif|left|200px]]
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{{STRUCTURE_1ppy|  PDB=1ppy  |  SCENE=  }}  
{{STRUCTURE_1ppy|  PDB=1ppy  |  SCENE=  }}  


'''Native precursor of pyruvoyl dependent Aspartate decarboxylase'''
===Native precursor of pyruvoyl dependent Aspartate decarboxylase===




==Overview==
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Aspartate decarboxylase, which is translated as a pro-protein, undergoes intramolecular self-cleavage at Gly24-Ser25. We have determined the crystal structures of an unprocessed native precursor, in addition to Ala24 insertion, Ala26 insertion and Gly24--&gt;Ser, His11--&gt;Ala, Ser25--&gt;Ala, Ser25--&gt;Cys and Ser25--&gt;Thr mutants. Comparative analyses of the cleavage site reveal specific conformational constraints that govern self-processing and demonstrate that considerable rearrangement must occur. We suggest that Thr57 Ogamma and a water molecule form an 'oxyanion hole' that likely stabilizes the proposed oxyoxazolidine intermediate. Thr57 and this water molecule are probable catalytic residues able to support acid-base catalysis. The conformational freedom in the loop preceding the cleavage site appears to play a determining role in the reaction. The molecular mechanism of self-processing, presented here, emphasizes the importance of stabilization of the oxyoxazolidine intermediate. Comparison of the structural features shows significant similarity to those in other self-processing systems, and suggests that models of the cleavage site of such enzymes based on Ser--&gt;Ala or Ser--&gt;Thr mutants alone may lead to erroneous interpretations of the mechanism.
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{{ABSTRACT_PUBMED_14633979}}


==About this Structure==
==About this Structure==
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[[Category: Intramolecular protein self-processing]]
[[Category: Intramolecular protein self-processing]]
[[Category: Pantothenate pathway]]
[[Category: Pantothenate pathway]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 05:21:04 2008''
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 03:39:48 2008''

Revision as of 03:39, 29 July 2008

File:1ppy.png

Template:STRUCTURE 1ppy

Native precursor of pyruvoyl dependent Aspartate decarboxylaseNative precursor of pyruvoyl dependent Aspartate decarboxylase

Template:ABSTRACT PUBMED 14633979

About this StructureAbout this Structure

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

ReferenceReference

Structural constraints on protein self-processing in L-aspartate-alpha-decarboxylase., Schmitzberger F, Kilkenny ML, Lobley CM, Webb ME, Vinkovic M, Matak-Vinkovic D, Witty M, Chirgadze DY, Smith AG, Abell C, Blundell TL, EMBO J. 2003 Dec 1;22(23):6193-204. PMID:14633979

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