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[[Image:1cqs.gif|left|200px]]<br /><applet load="1cqs" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1cqs, resolution 1.90&Aring;" />
'''CRYSTAL STRUCTURE OF D103E MUTANT WITH EQUILENINEOF KSI IN PSEUDOMONAS PUTIDA'''<br />


==Overview==
==CRYSTAL STRUCTURE OF D103E MUTANT WITH EQUILENINEOF KSI IN PSEUDOMONAS PUTIDA==
Delta 5-3-ketosteroid isomerase (KSI) catalyzes the allylic isomerization of Delta 5-3-ketosteroids at a rate approaching the diffusion limit by an intramolecular transfer of a proton. Despite the extensive studies on the catalytic mechanism, it still remains controversial whether the catalytic residue Asp-99 donates a hydrogen bond to the steroid or to Tyr-14. To clarify the role of Asp-99 in the catalysis, two single mutants of D99E and D99L and three double mutants of Y14F/D99E, Y14F/D99N, and Y14F/D99L have been prepared by site-directed mutagenesis. The D99E mutant whose side chain at position 99 is longer by an additional methylene group exhibits nearly the same kcat as the wild-type while the D99L mutant exhibits ca. 125-fold lower kcat than that of the wild-type. The mutations made at positions 14 and 99 exert synergistic or partially additive effect on kcat in the double mutants, which is inconsistent with the mechanism based on the hydrogen-bonded catalytic dyad, Asp-99 COOH...Tyr-14 OH...C3-O of the steroid. The crystal structure of D99E/D38N complexed with equilenin, an intermediate analogue, at 1.9 A resolution reveals that the distance between Tyr-14 O eta and Glu-99 O epsilon is ca. 4.2 A, which is beyond the range for a hydrogen bond, and that the distance between Glu-99 O epsilon and C3-O of the steroid is maintained to be ca. 2.4 A, short enough for a hydrogen bond to be formed. Taken together, these results strongly support the idea that Asp-99 contributes to the catalysis by donating a hydrogen bond directly to the intermediate.
<StructureSection load='1cqs' size='340' side='right'caption='[[1cqs]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1cqs]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CQS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1CQS 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]] 1.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EQU:EQUILENIN'>EQU</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=1cqs FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cqs OCA], [https://pdbe.org/1cqs PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1cqs RCSB], [https://www.ebi.ac.uk/pdbsum/1cqs PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1cqs ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SDIS_PSEPU SDIS_PSEPU]
== 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/cq/1cqs_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=1cqs ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1CQS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida] with <scene name='pdbligand=EQU:'>EQU</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Steroid_Delta-isomerase Steroid Delta-isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.3.1 5.3.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CQS OCA].
*[[Ketosteroid Isomerase|Ketosteroid Isomerase]]
 
__TOC__
==Reference==
</StructureSection>
Asp-99 donates a hydrogen bond not to Tyr-14 but to the steroid directly in the catalytic mechanism of Delta 5-3-ketosteroid isomerase from Pseudomonas putida biotype B., Choi G, Ha NC, Kim SW, Kim DH, Park S, Oh BH, Choi KY, Biochemistry. 2000 Feb 8;39(5):903-9. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=10653633 10653633]
[[Category: Large Structures]]
[[Category: Pseudomonas putida]]
[[Category: Pseudomonas putida]]
[[Category: Single protein]]
[[Category: Choi G]]
[[Category: Steroid Delta-isomerase]]
[[Category: Choi KY]]
[[Category: Choi, G.]]
[[Category: Ha NC]]
[[Category: Choi, K Y.]]
[[Category: Kim DH]]
[[Category: Ha, N C.]]
[[Category: Kim SW]]
[[Category: Kim, D H.]]
[[Category: Oh BH]]
[[Category: Kim, S W.]]
[[Category: Park S]]
[[Category: Oh, B H.]]
[[Category: Park, S.]]
[[Category: EQU]]
[[Category: equilenin]]
[[Category: ksi]]
[[Category: putida lbhb]]
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:08:46 2008''
Retrieved from "https://proteopedia.org/1cqs"