1tzm: Difference between revisions
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[[Image:1tzm.gif|left|200px]] | [[Image:1tzm.gif|left|200px]] | ||
'''Crystal structure of ACC deaminase complexed with substrate analog b-chloro-D-alanine''' | {{Structure | ||
|PDB= 1tzm |SIZE=350|CAPTION= <scene name='initialview01'>1tzm</scene>, resolution 2.08Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=PLP:PYRIDOXAL-5'-PHOSPHATE'>PLP</scene>, <scene name='pdbligand=C2N:B-CHLORO-D-ALANINE'>C2N</scene> and <scene name='pdbligand=NAK:AMINO-ACRYLATE'>NAK</scene> | |||
|ACTIVITY= [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] | |||
|GENE= | |||
}} | |||
'''Crystal structure of ACC deaminase complexed with substrate analog b-chloro-D-alanine''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1TZM is a [ | 1TZM is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_sp. Pseudomonas sp.]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TZM OCA]. | ||
==Reference== | ==Reference== | ||
Structural analysis of Pseudomonas 1-aminocyclopropane-1-carboxylate deaminase complexes: insight into the mechanism of a unique pyridoxal-5'-phosphate dependent cyclopropane ring-opening reaction., Karthikeyan S, Zhou Q, Zhao Z, Kao CL, Tao Z, Robinson H, Liu HW, Zhang H, Biochemistry. 2004 Oct 26;43(42):13328-39. PMID:[http:// | Structural analysis of Pseudomonas 1-aminocyclopropane-1-carboxylate deaminase complexes: insight into the mechanism of a unique pyridoxal-5'-phosphate dependent cyclopropane ring-opening reaction., Karthikeyan S, Zhou Q, Zhao Z, Kao CL, Tao Z, Robinson H, Liu HW, Zhang H, Biochemistry. 2004 Oct 26;43(42):13328-39. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15491139 15491139] | ||
[[Category: 1-aminocyclopropane-1-carboxylate deaminase]] | [[Category: 1-aminocyclopropane-1-carboxylate deaminase]] | ||
[[Category: Pseudomonas sp.]] | [[Category: Pseudomonas sp.]] | ||
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[[Category: substrate]] | [[Category: substrate]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 14:25:18 2008'' | ||
Revision as of 15:25, 20 March 2008
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| , resolution 2.08Å | |||||||
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| Ligands: | , , and | ||||||
| Activity: | 1-aminocyclopropane-1-carboxylate deaminase, with EC number 3.5.99.7 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal structure of ACC deaminase complexed with substrate analog b-chloro-D-alanine
OverviewOverview
1-Aminocyclopropane-1-carboxylate (ACC) deaminase is a pyridoxal 5'-phosphate (PLP) dependent enzyme catalyzing the opening of the cyclopropane ring of ACC to give alpha-ketobutyric acid and ammonia as the products. This ring cleavage reaction is unusual because the substrate, ACC, contains no abstractable alpha-proton and the carboxyl group is retained in the product. How the reaction is initiated to generate an alpha-carbanionic intermediate, which is the common entry for most PLP-dependent reactions, is not obvious. To gain insight into this unusual ring-opening reaction, we have solved the crystal structures of ACC deaminase from Pseudomonas sp. ACP in complex with substrate ACC, an inhibitor, 1-aminocyclopropane-1-phosphonate (ACP), the product alpha-ketobutyrate, and two d-amino acids. Several notable observations of these structural studies include the following: (1) a typically elusive gem-diamine intermediate is trapped in the enzyme complex with ACC or ACP; (2) Tyr294 is in close proximity (3.0 A) to the pro-S methylene carbon of ACC in the gem-diamine complexes, implicating a direct role of this residue in the ring-opening reaction; (3) Tyr294 may also be responsible for the abstraction of the alpha-proton from d-amino acids, a prelude to the subsequent deamination reaction; (4) the steric hindrance precludes accessibility of active site functional groups to the l-amino acid substrates and may account for the stereospecificity of this enzyme toward d-amino acids. These structural data provide evidence favoring a mechanism in which the ring cleavage is induced by a nucleophilic attack at the pro-S beta-methylene carbon of ACC, with Tyr294 as the nucleophile. However, these observations are also consistent with an alternative mechanistic possibility in which the ring opening is acid-catalyzed and may be facilitated by charge relay through PLP, where Tyr294 functions as a general acid. The results of mutagenesis studies corroborated the assigned critical role for Tyr294 in the catalysis.
About this StructureAbout this Structure
1TZM is a Single protein structure of sequence from Pseudomonas sp.. Full crystallographic information is available from OCA.
ReferenceReference
Structural analysis of Pseudomonas 1-aminocyclopropane-1-carboxylate deaminase complexes: insight into the mechanism of a unique pyridoxal-5'-phosphate dependent cyclopropane ring-opening reaction., Karthikeyan S, Zhou Q, Zhao Z, Kao CL, Tao Z, Robinson H, Liu HW, Zhang H, Biochemistry. 2004 Oct 26;43(42):13328-39. PMID:15491139
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