1j0c
From Proteopedia
(New page: 200px<br /><applet load="1j0c" size="450" color="white" frame="true" align="right" spinBox="true" caption="1j0c, resolution 2.75Å" /> '''ACC deaminase mutate...) |
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| - | [[Image:1j0c.jpg|left|200px]]<br /><applet load="1j0c" size=" | + | [[Image:1j0c.jpg|left|200px]]<br /><applet load="1j0c" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1j0c, resolution 2.75Å" /> | caption="1j0c, resolution 2.75Å" /> | ||
'''ACC deaminase mutated to catalytic residue'''<br /> | '''ACC deaminase mutated to catalytic residue'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The pyridoxal 5'-phosphate-dependent enzymes have been evolved to catalyze | + | The pyridoxal 5'-phosphate-dependent enzymes have been evolved to catalyze diverse substrates and to cause the reaction to vary. 1-Aminocyclopropane-1-carboxylate deaminase catalyzes the cyclopropane ring-opening reaction followed by deamination specifically. Since it was discovered in 1978, the enzyme has been widely investigated from the mechanistic and physiological viewpoints because the substrate is a precursor of the plant hormone ethylene and the enzymatic reaction includes a cyclopropane ring-opening. We have previously reported the crystal structure of the native enzyme. Here we report the crystal structures of the two reaction intermediates created by the mutagenesis complexed with the substrate. The substrate was validated in the active site of two forms: 1). covalent-bonded external aldimine with the coenzyme in the K51T form and 2). the non-covalent interaction around the coenzyme in the Y295F form. The orientations of the substrate in both structures were quite different form each other. In concert with other site-specific mutation experiments, this experiment revealed the ingenious and unique strategies that are used to achieve the specific activity. The substrate incorporated into the active site is reactivated by a two-phenol charge relay system to lead to the formation of a Schiff base with the coenzyme. The catalytic Lys51 residue may play a novel role to abstract the methylene proton from the substrate in cooperation with other factors, the carboxylate group of the substrate and the electron-adjusting apparatuses of the coenzyme. |
==About this Structure== | ==About this Structure== | ||
| - | 1J0C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Williopsis_saturnus Williopsis saturnus] with PLP as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/1-aminocyclopropane-1-carboxylate_deaminase 1-aminocyclopropane-1-carboxylate deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.99.7 3.5.99.7] Full crystallographic information is available from [http:// | + | 1J0C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Williopsis_saturnus Williopsis saturnus] with <scene name='pdbligand=PLP:'>PLP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/1-aminocyclopropane-1-carboxylate_deaminase 1-aminocyclopropane-1-carboxylate deaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.99.7 3.5.99.7] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1J0C OCA]. |
==Reference== | ==Reference== | ||
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[[Category: plp dependent b group]] | [[Category: plp dependent b group]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:17:36 2008'' |
Revision as of 11:17, 21 February 2008
|
ACC deaminase mutated to catalytic residue
Overview
The pyridoxal 5'-phosphate-dependent enzymes have been evolved to catalyze diverse substrates and to cause the reaction to vary. 1-Aminocyclopropane-1-carboxylate deaminase catalyzes the cyclopropane ring-opening reaction followed by deamination specifically. Since it was discovered in 1978, the enzyme has been widely investigated from the mechanistic and physiological viewpoints because the substrate is a precursor of the plant hormone ethylene and the enzymatic reaction includes a cyclopropane ring-opening. We have previously reported the crystal structure of the native enzyme. Here we report the crystal structures of the two reaction intermediates created by the mutagenesis complexed with the substrate. The substrate was validated in the active site of two forms: 1). covalent-bonded external aldimine with the coenzyme in the K51T form and 2). the non-covalent interaction around the coenzyme in the Y295F form. The orientations of the substrate in both structures were quite different form each other. In concert with other site-specific mutation experiments, this experiment revealed the ingenious and unique strategies that are used to achieve the specific activity. The substrate incorporated into the active site is reactivated by a two-phenol charge relay system to lead to the formation of a Schiff base with the coenzyme. The catalytic Lys51 residue may play a novel role to abstract the methylene proton from the substrate in cooperation with other factors, the carboxylate group of the substrate and the electron-adjusting apparatuses of the coenzyme.
About this Structure
1J0C is a Single protein structure of sequence from Williopsis saturnus with as ligand. Active as 1-aminocyclopropane-1-carboxylate deaminase, with EC number 3.5.99.7 Full crystallographic information is available from OCA.
Reference
Reaction intermediate structures of 1-aminocyclopropane-1-carboxylate deaminase: insight into PLP-dependent cyclopropane ring-opening reaction., Ose T, Fujino A, Yao M, Watanabe N, Honma M, Tanaka I, J Biol Chem. 2003 Oct 17;278(42):41069-76. Epub 2003 Jul 26. PMID:12882962
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