1jsr
From Proteopedia
(New page: 200px<br /><applet load="1jsr" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jsr, resolution 1.70Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1jsr.gif|left|200px]]<br /><applet load="1jsr" size=" | + | [[Image:1jsr.gif|left|200px]]<br /><applet load="1jsr" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1jsr, resolution 1.70Å" /> | caption="1jsr, resolution 1.70Å" /> | ||
'''CRYSTAL STRUCTURE OF ERWINIA CHRYSANTHEMI L-ASPARAGINASE COMPLEXED WITH 6-HYDROXY-L-NORLEUCINE'''<br /> | '''CRYSTAL STRUCTURE OF ERWINIA CHRYSANTHEMI L-ASPARAGINASE COMPLEXED WITH 6-HYDROXY-L-NORLEUCINE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structures of Erwinia chrysanthemi L-asparaginase (ErA) complexed with | + | The structures of Erwinia chrysanthemi L-asparaginase (ErA) complexed with the L- and D-stereoisomers of the suicide inhibitor, 6-diazo-5-oxy-norleucine, have been solved using X-ray crystallography and refined with data extending to 1.7 A. The distances between the Calpha atoms of the inhibitor molecules and the hydroxyl oxygen atoms of Thr-15 and Tyr-29 (1.20 and 1.60 A, respectively) clearly indicate the presence of covalent bonds between these moieties, confirming the nucleophilic role of Thr-15 during the first stage of enzymatic reactions and also indicating direct involvement of Tyr-29. The factors responsible for activating Tyr-29 remain unclear, although some structural changes around Ser-254', Asp-96, and Glu-63, common to both complexes, suggest that those residues play a function. The role of Glu-289' as the activator of Tyr-29, previously postulated for the closely related Pseudomonas 7A L-glutaminase-asparaginase, is not confirmed in this study, due to the lack of interactions between these residues in these complexes and in holoenzymes. The results reported here are consistent with previous reports that mutants of Escherichia coli L-asparaginase lacking Glu-289 remain catalytically active and prove the catalytic roles of both Thr-15 and Tyr-29, while still leaving open the question of the exact mechanism resulting in the unusual chemical properties of these residues. |
==About this Structure== | ==About this Structure== | ||
| - | 1JSR is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Erwinia_chrysanthemi Erwinia chrysanthemi] with LDO, 1PE and GOL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Asparaginase Asparaginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.1 3.5.1.1] Full crystallographic information is available from [http:// | + | 1JSR is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Erwinia_chrysanthemi Erwinia chrysanthemi] with <scene name='pdbligand=LDO:'>LDO</scene>, <scene name='pdbligand=1PE:'>1PE</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Asparaginase Asparaginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.1 3.5.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JSR OCA]. |
==Reference== | ==Reference== | ||
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[[Category: x-ray]] | [[Category: x-ray]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:26:17 2008'' |
Revision as of 11:26, 21 February 2008
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CRYSTAL STRUCTURE OF ERWINIA CHRYSANTHEMI L-ASPARAGINASE COMPLEXED WITH 6-HYDROXY-L-NORLEUCINE
Overview
The structures of Erwinia chrysanthemi L-asparaginase (ErA) complexed with the L- and D-stereoisomers of the suicide inhibitor, 6-diazo-5-oxy-norleucine, have been solved using X-ray crystallography and refined with data extending to 1.7 A. The distances between the Calpha atoms of the inhibitor molecules and the hydroxyl oxygen atoms of Thr-15 and Tyr-29 (1.20 and 1.60 A, respectively) clearly indicate the presence of covalent bonds between these moieties, confirming the nucleophilic role of Thr-15 during the first stage of enzymatic reactions and also indicating direct involvement of Tyr-29. The factors responsible for activating Tyr-29 remain unclear, although some structural changes around Ser-254', Asp-96, and Glu-63, common to both complexes, suggest that those residues play a function. The role of Glu-289' as the activator of Tyr-29, previously postulated for the closely related Pseudomonas 7A L-glutaminase-asparaginase, is not confirmed in this study, due to the lack of interactions between these residues in these complexes and in holoenzymes. The results reported here are consistent with previous reports that mutants of Escherichia coli L-asparaginase lacking Glu-289 remain catalytically active and prove the catalytic roles of both Thr-15 and Tyr-29, while still leaving open the question of the exact mechanism resulting in the unusual chemical properties of these residues.
About this Structure
1JSR is a Single protein structure of sequence from Erwinia chrysanthemi with , and as ligands. Active as Asparaginase, with EC number 3.5.1.1 Full crystallographic information is available from OCA.
Reference
Do bacterial L-asparaginases utilize a catalytic triad Thr-Tyr-Glu?, Aghaiypour K, Wlodawer A, Lubkowski J, Biochim Biophys Acta. 2001 Dec 17;1550(2):117-28. PMID:11755201
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