View source for 1ajb


==THREE-DIMENSIONAL STRUCTURE OF THE D153G MUTANT OF E. COLI ALKALINE PHOSPHATASE: A MUTANT WITH WEAKER MAGNESIUM BINDING AND INCREASED CATALYTIC ACTIVITY==
<StructureSection load='1ajb' size='340' side='right'caption='[[1ajb]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ajb]] 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=1AJB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AJB 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=1ajb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ajb OCA], [https://pdbe.org/1ajb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ajb RCSB], [https://www.ebi.ac.uk/pdbsum/1ajb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ajb ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PPB_ECOLI PPB_ECOLI] 
== 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/aj/1ajb_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1ajb ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
The substitution of aspartate at position 153 in Escherichia coli alkaline phosphatase by glycine results in a mutant enzyme with 5-fold higher catalytic activity (kcat) but no change in Km at pH 8.0 in 50 mM Tris-HCl. The increased kcat is achieved by a faster release of the phosphate product as a result of the lower phosphate affinity. The mutation also affects Mg2+ binding, resulting in an enzyme with lower metal affinity. The 3-D X-ray structure of the D153G mutant has been refined at 2.5 A to a crystallographic R-factor of 16.2%. An analysis of this structure has revealed that the decreased phosphate affinity is caused by an apparent increase in flexibility of the guanidinium side chain of Arg166 involved in phosphate binding. The mutation of Asp153 to Gly also affects the position of the water ligands of Mg2+, and the loop Gln152-Thr155 is shifted by 0.3 A away from the active site. The weaker Mg2+ binding of the mutant compared with the wild type is caused by an altered coordination sphere in the proximity of the Mg2+ ion, and also by the loss of an electrostatic interaction (Mg2+.COO-Asp153) in the mutant. Its ligands W454 and W455 and hydroxyl of Thr155, involved in the octahedral coordination of the Mg2+ ion, are further apart in the mutant compared with the wild type.

3-D structure of the D153G mutant of Escherichia coli alkaline phosphatase: an enzyme with weaker magnesium binding and increased catalytic activity.,Dealwis CG, Chen L, Brennan C, Mandecki W, Abad-Zapatero C Protein Eng. 1995 Sep;8(9):865-71. PMID:8746724<ref>PMID:8746724</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1ajb" style="background-color:#fffaf0;"></div>

==See Also==
*[[Alkaline phosphatase 3D structures|Alkaline phosphatase 3D structures]]
*[[Gyrase 3D Structures|Gyrase 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Abad-Zapatero C]]
[[Category: Chen L]]
[[Category: Dealwis CG]]