This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1pqh
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1pqh.jpg|left|200px]] | [[Image:1pqh.jpg|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1pqh", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | | | + | --> |
| - | | | + | {{STRUCTURE_1pqh| PDB=1pqh | SCENE= }} |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''Serine 25 to Threonine mutation of aspartate decarboxylase''' | '''Serine 25 to Threonine mutation of aspartate decarboxylase''' | ||
| Line 37: | Line 34: | ||
[[Category: Webb, M E.]] | [[Category: Webb, M E.]] | ||
[[Category: Witty, M.]] | [[Category: Witty, M.]] | ||
| - | [[Category: | + | [[Category: Protein self-processing]] |
| - | [[Category: | + | [[Category: Pyruvoyl dependent decarboxylase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 05:22:08 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 02:22, 3 May 2008
Serine 25 to Threonine mutation of aspartate decarboxylase
Overview
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 Structure
1PQH is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Sat May 3 05:22:08 2008
Categories: Aspartate 1-decarboxylase | Escherichia coli | Single protein | Abell, C. | Blundell, T L. | Chirgadze, D Y. | Kilkenny, M L. | Lobley, C M.C. | Matak-Vinkovic, D. | Schmitzberger, F. | Smith, A G. | Vinkovic, M. | Webb, M E. | Witty, M. | Protein self-processing | Pyruvoyl dependent decarboxylase
