1ppy
Native precursor of pyruvoyl dependent Aspartate decarboxylase
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OverviewOverview
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-->Ser, His11-->Ala, Ser25-->Ala, Ser25-->Cys and Ser25-->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-->Ala or, Ser-->Thr mutants alone may lead to erroneous interpretations of the, mechanism.
About this StructureAbout this Structure
1PPY is a Single protein structure of sequence from Escherichia coli with SO4 as ligand. Active as Aspartate 1-decarboxylase, with EC number 4.1.1.11 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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