3bk9: Difference between revisions
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==H55A mutant of tryptophan 2,3-dioxygenase from Xanthomonas campestris== | ==H55A mutant of tryptophan 2,3-dioxygenase from Xanthomonas campestris== | ||
<StructureSection load='3bk9' size='340' side='right' caption='[[3bk9]], [[Resolution|resolution]] 2.15Å' scene=''> | <StructureSection load='3bk9' size='340' side='right'caption='[[3bk9]], [[Resolution|resolution]] 2.15Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[3bk9]] is a 8 chain structure with sequence from [http://en.wikipedia.org/wiki/Xance Xance]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BK9 OCA]. For a <b>guided tour on the structure components</b> use [http:// | <table><tr><td colspan='2'>[[3bk9]] is a 8 chain structure with sequence from [http://en.wikipedia.org/wiki/Xance Xance]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BK9 OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=3BK9 FirstGlance]. <br> | ||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=TRP:TRYPTOPHAN'>TRP</scene></td></tr> | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=TRP:TRYPTOPHAN'>TRP</scene></td></tr> | ||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2nw7|2nw7]], [[2nw8|2nw8]], [[2nw9|2nw9]], [[3e08|3e08]]</td></tr> | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2nw7|2nw7]], [[2nw8|2nw8]], [[2nw9|2nw9]], [[3e08|3e08]]</td></tr> | ||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Tryptophan_2,3-dioxygenase Tryptophan 2,3-dioxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.13.11.11 1.13.11.11] </span></td></tr> | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Tryptophan_2,3-dioxygenase Tryptophan 2,3-dioxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.13.11.11 1.13.11.11] </span></td></tr> | ||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http:// | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=3bk9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3bk9 OCA], [http://pdbe.org/3bk9 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3bk9 RCSB], [http://www.ebi.ac.uk/pdbsum/3bk9 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3bk9 ProSAT]</span></td></tr> | ||
</table> | </table> | ||
== Function == | == Function == | ||
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==See Also== | ==See Also== | ||
*[[Dioxygenase|Dioxygenase]] | *[[Dioxygenase 3D structures|Dioxygenase 3D structures]] | ||
== References == | == References == | ||
<references/> | <references/> | ||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Large Structures]] | |||
[[Category: Tryptophan 2,3-dioxygenase]] | [[Category: Tryptophan 2,3-dioxygenase]] | ||
[[Category: Xance]] | [[Category: Xance]] | ||
Revision as of 09:18, 5 August 2020
H55A mutant of tryptophan 2,3-dioxygenase from Xanthomonas campestrisH55A mutant of tryptophan 2,3-dioxygenase from Xanthomonas campestris
Structural highlights
Function[T23O_XANCP] Catalyzes the oxidative cleavage of the L-tryptophan (L-Trp) pyrrole ring.[HAMAP-Rule:MF_01972][1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTryptophan 2,3-dioxygenase (TDO) from Xanthomonas campestris is a highly specific heme-containing enzyme from a small family of homologous enzymes, which includes indoleamine 2,3-dioxygenase (IDO). The structure of wild type (WT TDO) in the catalytically active, ferrous (Fe (2+)) form and in complex with its substrate l-tryptophan ( l-Trp) was recently reported [Forouhar et al. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 473-478] and revealed that histidine 55 hydrogen bonds to l-Trp, precisely positioning it in the active site and implicating it as a possible active site base. In this study the substitution of the active site residue histidine 55 by alanine and serine (H55A and H55S) provides insight into the molecular mechanism used by the enzyme to control substrate binding. We report the crystal structure of the H55A and H55S mutant forms at 2.15 and 1.90 A resolution, respectively, in binary complexes with l-Trp. These structural data, in conjunction with potentiometric and kinetic studies on both mutants, reveal that histidine 55 is not essential for turnover but greatly disfavors the mechanistically unproductive binding of l-Trp to the oxidized enzyme allowing control of catalysis. This is demonstrated by the difference in the K d values for l-Trp binding to the two oxidation states of wild-type TDO (3.8 mM oxidized, 4.1 microM reduced), H55A TDO (11.8 microM oxidized, 3.7 microM reduced), and H55S TDO (18.4 microM oxidized, 5.3 microM reduced). Histidine 55 of tryptophan 2,3-dioxygenase is not an active site base but regulates catalysis by controlling substrate binding.,Thackray SJ, Bruckmann C, Anderson JL, Campbell LP, Xiao R, Zhao L, Mowat CG, Forouhar F, Tong L, Chapman SK Biochemistry. 2008 Oct 7;47(40):10677-84. Epub 2008 Sep 11. PMID:18783250[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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