1qt8: Difference between revisions

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-[[Image:1qt8.jpg|left|200px]]<br /><applet load="1qt8" size="450" color="white" frame="true" align="right" spinBox="true"
-caption="1qt8, resolution 1.9&Aring;" />
-'''T26H Mutant of T4 Lysozyme'''<br />
-==Overview==
+==T26H Mutant of T4 Lysozyme==
-In contrast to hen egg-white lysozyme, which retains the, beta-configuration of the substrate in the product, T4 lysozyme (T4L) is, an inverting glycosidase. The substitution Thr-26 --&gt; His, however, converts T4L from an inverting to a retaining enzyme. It is shown here, that the Thr-26 --&gt; His mutant is also a transglycosidase. Indeed, the, transglycosylation reaction can be more effective than hydrolysis. In, contrast, wild-type T4L has no detectable transglycosidase activity. The, results support the prior hypothesis that catalysis by the Thr-26 --&gt; His, mutant proceeds via a covalent intermediate. Further mutations (Glu-11 --&gt;, His, Asp-20 --&gt; Cys) of the T26H mutant lysozyme indicate that the, catalytic mechanism of this mutant requires Glu-11 as a general acid but, Asp-20 is not essential. The results help provide an overall, rationalization for the activity of glycosidases, in which a highly, conserved acid group (Glu-11 in T4L, Glu-35 in hen egg-white lysozyme) on, the beta-side of the substrate acts as a proton donor, whereas alterations, in the placement and chemical identity of residues on the alpha-side of, the substrate can lead to catalysis with or without retention of the, configuration, to transglycosidase activity, or to the formation of a, stable enzyme-substrate adduct.
+<StructureSection load='1qt8' size='340' side='right'caption='[[1qt8]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
+== Structural highlights ==
+<table><tr><td colspan='2'>[[1qt8]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_virus_T4 Escherichia virus T4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QT8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QT8 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=HED:2-HYDROXYETHYL+DISULFIDE'>HED</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=1qt8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qt8 OCA], [https://pdbe.org/1qt8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1qt8 RCSB], [https://www.ebi.ac.uk/pdbsum/1qt8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1qt8 ProSAT]</span></td></tr>
+</table>
+== Function ==
+[https://www.uniprot.org/uniprot/ENLYS_BPT4 ENLYS_BPT4] Endolysin with lysozyme activity that degrades host peptidoglycans and participates with the holin and spanin proteins in the sequential events which lead to the programmed host cell lysis releasing the mature viral particles. Once the holin has permeabilized the host cell membrane, the endolysin can reach the periplasm and break down the peptidoglycan layer.<ref>PMID:22389108</ref>
+== 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/qt/1qt8_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=1qt8 ConSurf].
+<div style="clear:both"></div>
-==About this Structure==
+==See Also==
-QT8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_phage_d3112 Pseudomonas phage d3112] with HED as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1QT8 OCA].
+*[[Lysozyme 3D structures|Lysozyme 3D structures]]
+== References ==
-==Reference==
+<references/>
-Structural basis of the conversion of T4 lysozyme into a transglycosidase by reengineering the active site., Kuroki R, Weaver LH, Matthews BW, Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):8949-54. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=10430876 10430876]
+__TOC__
-[[Category: Lysozyme]]
+</StructureSection>
-[[Category: Pseudomonas phage d3112]]
+[[Category: Escherichia virus T4]]
-[[Category: Single protein]]
+[[Category: Large Structures]]
-[[Category: Kuroki, R.]]
+[[Category: Kuroki R]]
-[[Category: Matthews, B.W.]]
+[[Category: Matthews BW]]
-[[Category: Weaver, L.H.]]
+[[Category: Weaver LH]]
-[[Category: HED]]
-[[Category: hydrolase]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 00:57:46 2007''