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[[Image:1l75.jpg|left|200px]]<br /><applet load="1l75" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1l75, resolution 1.9&Aring;" />
'''MULTIPLE STABILIZING ALANINE REPLACEMENTS WITHIN ALPHA-HELIX 126-134 OF T4 LYSOZYME HAVE INDEPENDENT, ADDITIVE EFFECTS ON BOTH STRUCTURE AND STABILITY'''<br />


==Overview==
==MULTIPLE STABILIZING ALANINE REPLACEMENTS WITHIN ALPHA-HELIX 126-134 OF T4 LYSOZYME HAVE INDEPENDENT, ADDITIVE EFFECTS ON BOTH STRUCTURE AND STABILITY==
In a systematic attempt to identify residues important in the folding and stability of T4 lysozyme, five amino acids within alpha-helix 126-134 were substituted by alanine, either singly or in selected combinations. Together with three alanines already present in the wild-type structure this provided a set of mutant proteins with up to eight alanines in sequence. All the variants behaved normally, suggesting that the majority of residues in the alpha-helix are nonessential for the folding of T4 lysozyme. Of the five individual alanine substitutions it is inferred that four result in slightly increased protein stability and one, the replacement of a buried leucine with alanine, substantially decreased stability. The results support the idea that alanine is a residue of high helix propensity. The change in protein stability observed for each of the multiple mutants is approximately equal to the sum of the energies associated with each of the constituent substitutions. All of the variants could be crystallized isomorphously with wild-type lysozyme, and, with one trivial exception, their structures were determined at high resolution. Substitution of the largely solvent-exposed residues Asp 127, Glu 128, and Val 131 with alanine caused essentially no change in structure except at the immediate site of replacement. Substitutions of the partially buried Asn 132 and the buried Leu 133 with alanine were associated with modest (&lt; or = 0.4 A) structural adjustments. The structural changes seen in the multiple mutants were essentially a combination of those seen in the constituent single replacements. The different replacements therefore act essentially independently not only so far as changes in energy are concerned but also in their effect on structure. The destabilizing replacement Leu 133--&gt;Ala made alpha-helix 126-134 somewhat less regular. Incorporation of additional alanine replacements tended to make the helix more uniform. For the penta-alanine variant a distinct change occurred in a crystal-packing contact, and the "hinge-bending angle" between the amino- and carboxy-terminal domains changed by 3.6 degrees. This tends to confirm that such hinge-bending in T4 lysozyme is a low-energy conformational change.
<StructureSection load='1l75' size='340' side='right'caption='[[1l75]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1l75]] 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=1L75 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1L75 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=BME:BETA-MERCAPTOETHANOL'>BME</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</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=1l75 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1l75 OCA], [https://pdbe.org/1l75 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1l75 RCSB], [https://www.ebi.ac.uk/pdbsum/1l75 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1l75 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/l7/1l75_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=1l75 ConSurf].
<div style="clear:both"></div>


==About this Structure==
==See Also==
1L75 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4] with <scene name='pdbligand=CL:'>CL</scene> and <scene name='pdbligand=BME:'>BME</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. 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://oca.weizmann.ac.il/oca-bin/ocashort?id=1L75 OCA].
*[[Lysozyme 3D structures|Lysozyme 3D structures]]
 
== References ==
==Reference==
<references/>
Multiple alanine replacements within alpha-helix 126-134 of T4 lysozyme have independent, additive effects on both structure and stability., Zhang XJ, Baase WA, Matthews BW, Protein Sci. 1992 Jun;1(6):761-76. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=1304917 1304917]
__TOC__
[[Category: Bacteriophage t4]]
</StructureSection>
[[Category: Lysozyme]]
[[Category: Escherichia virus T4]]
[[Category: Single protein]]
[[Category: Large Structures]]
[[Category: Matthews, B W.]]
[[Category: Matthews BW]]
[[Category: Zhang, X.]]
[[Category: Zhang X]]
[[Category: BME]]
[[Category: CL]]
[[Category: hydrolase (o-glycosyl)]]
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:42:06 2008''

Latest revision as of 11:07, 3 April 2024

MULTIPLE STABILIZING ALANINE REPLACEMENTS WITHIN ALPHA-HELIX 126-134 OF T4 LYSOZYME HAVE INDEPENDENT, ADDITIVE EFFECTS ON BOTH STRUCTURE AND STABILITYMULTIPLE STABILIZING ALANINE REPLACEMENTS WITHIN ALPHA-HELIX 126-134 OF T4 LYSOZYME HAVE INDEPENDENT, ADDITIVE EFFECTS ON BOTH STRUCTURE AND STABILITY

Structural highlights

1l75 is a 1 chain structure with sequence from Escherichia virus T4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.9Å
Ligands:,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

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.[1]

Evolutionary Conservation

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

See Also

References

  1. ↑ Moussa SH, Kuznetsov V, Tran TA, Sacchettini JC, Young R. Protein determinants of phage T4 lysis inhibition. Protein Sci. 2012 Apr;21(4):571-82. doi: 10.1002/pro.2042. Epub 2012 Mar 2. PMID:22389108 doi:http://dx.doi.org/10.1002/pro.2042

1l75, resolution 1.90Å

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