1tz2: Difference between revisions

<StructureSection load='1tz2' size='340' side='right'caption='[[1tz2]], [[Resolution|resolution]] 2.10&Aring;' scene=''>

<table><tr><td colspan='2'>[[1tz2]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Pseudomonas_sp._ACP Pseudomonas sp. ACP]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TZ2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1TZ2 FirstGlance]. <br>

</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.1&#8491;</td></tr>

<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=1AC:1-AMINOCYCLOPROPANECARBOXYLIC+ACID'>1AC</scene>, <scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1tz2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1tz2 OCA], [https://pdbe.org/1tz2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1tz2 RCSB], [https://www.ebi.ac.uk/pdbsum/1tz2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1tz2 ProSAT]</span></td></tr>

    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/tz/1tz2_consurf.spt"</scriptWhenChecked>

    <text>to colour the structure by Evolutionary Conservation</text>

</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1tz2 ConSurf].

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.

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<ref>PMID:15491139</ref>

==See Also==

*[[Deaminase 3D structures|Deaminase 3D structures]]

== References ==

<references/>

</StructureSection>

[[Category: Large Structures]]

[[Category: Pseudomonas sp. ACP]]

[[Category: Kao CL]]

[[Category: Karthikeyan S]]

[[Category: Liu HW]]

[[Category: Robinson H]]

[[Category: Tao Z]]

[[Category: Zhang H]]

[[Category: Zhao Z]]

[[Category: Zhou Q]]