1gm7: Difference between revisions

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[[Image:1gm7.gif|left|200px]]<br />
<applet load="1gm7" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1gm7, resolution 1.45&Aring;" />
'''CRYSTAL STRUCTURES OF PENICILLIN ACYLASE ENZYME-SUBSTRATE COMPLEXES: STRUCTURAL INSIGHTS INTO THE CATALYTIC MECHANISM'''<br />


==Overview==
==Crystal structures of penicillin acylase enzyme-substrate complexes: Structural insights into the catalytic mechanism==
The crystal structure of penicillin G acylase from Escherichia coli has, been determined to a resolution of 1.3 A from a crystal form grown in the, presence of ethylene glycol. To study aspects of the substrate specificity, and catalytic mechanism of this key biotechnological enzyme, mutants were, made to generate inactive protein useful for producing enzyme-substrate, complexes. Owing to the intimate association of enzyme activity and, precursor processing in this protein family (the Ntn hydrolases), most, attempts to alter active-site residues lead to processing defects., Mutation of the invariant residue Arg B263 results in the accumulation of, a protein precursor form. However, the mutation of Asn B241, a residue, implicated in stabilisation of the tetrahedral intermediate during, catalysis, inactivates the enzyme but does not prevent autocatalytic, processing or the ability to bind substrates. The crystal structure of the, Asn B241 Ala oxyanion hole mutant enzyme has been determined in its native, form and in complex with penicillin G and penicillin G sulphoxide. We show, that Asn B241 has an important role in maintaining the active site, geometry and in productive substrate binding, hence the structure of the, mutant protein is a poor model for the Michaelis complex. For this reason, we subsequently solved the structure of the wild-type protein in complex, with the slowly processed substrate penicillin G sulphoxide. Analysis of, this structure suggests that the reaction mechanism proceeds via direct, nucleophilic attack of Ser B1 on the scissile amide and not as previously, proposed via a tightly H-bonded water molecule acting as a "virtual" base.
<StructureSection load='1gm7' size='340' side='right'caption='[[1gm7]], [[Resolution|resolution]] 1.45&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1gm7]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GM7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1GM7 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]] 1.45&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=PNN:PENICILLIN+G'>PNN</scene>, <scene name='pdbligand=SME:METHIONINE+SULFOXIDE'>SME</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=1gm7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1gm7 OCA], [https://pdbe.org/1gm7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1gm7 RCSB], [https://www.ebi.ac.uk/pdbsum/1gm7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1gm7 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PAC_ECOLX PAC_ECOLX]
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/gm/1gm7_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</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=1gm7 ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1GM7 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with PNN, CA and EDO as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Penicillin_amidase Penicillin amidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.11 3.5.1.11] Structure known Active Site: CA1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GM7 OCA].
*[[Penicillin acylase|Penicillin acylase]]
 
__TOC__
==Reference==
</StructureSection>
Crystal structures of penicillin acylase enzyme-substrate complexes: structural insights into the catalytic mechanism., McVey CE, Walsh MA, Dodson GG, Wilson KS, Brannigan JA, J Mol Biol. 2001 Oct 12;313(1):139-50. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11601852 11601852]
[[Category: Escherichia coli]]
[[Category: Escherichia coli]]
[[Category: Penicillin amidase]]
[[Category: Large Structures]]
[[Category: Protein complex]]
[[Category: Brannigan JA]]
[[Category: Brannigan, J.A.]]
[[Category: Dodson GG]]
[[Category: Dodson, G.G.]]
[[Category: McVey CE]]
[[Category: Mcvey, C.E.]]
[[Category: Walsh MA]]
[[Category: Walsh, M.A.]]
[[Category: Wilson KS]]
[[Category: Wilson, K.S.]]
[[Category: CA]]
[[Category: EDO]]
[[Category: PNN]]
[[Category: antibiotic resistance]]
[[Category: hydrolase]]
 
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov  5 13:40:47 2007''

Latest revision as of 14:22, 27 March 2024

Crystal structures of penicillin acylase enzyme-substrate complexes: Structural insights into the catalytic mechanismCrystal structures of penicillin acylase enzyme-substrate complexes: Structural insights into the catalytic mechanism

Structural highlights

1gm7 is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.45Å
Ligands:, , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

PAC_ECOLX

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

1gm7, resolution 1.45Å

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