View source for 249l

==THE RESPONSE OF T4 LYSOZYME TO LARGE-TO-SMALL SUBSTITUTIONS WITHIN THE CORE AND ITS RELATION TO THE HYDROPHOBIC EFFECT==
<StructureSection load='249l' size='340' side='right' caption='[[249l]], [[Resolution|resolution]] 1.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[249l]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Enterobacteria_phage_t4 Enterobacteria phage t4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=249L OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=249L FirstGlance]. <br>
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=HED:2-HYDROXYETHYL+DISULFIDE'>HED</scene><br>
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2lzm|2lzm]], [[3lzm|3lzm]]</td></tr>
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">T4 LYSOZYME GENE ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10665 Enterobacteria phage T4])</td></tr>
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[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] </span></td></tr>
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=249l FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=249l OCA], [http://www.rcsb.org/pdb/explore.do?structureId=249l RCSB], [http://www.ebi.ac.uk/pdbsum/249l PDBsum]</span></td></tr>
<table>
== 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/49/249l_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/chain_selection.php?pdb_ID=2ata ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
To further examine the structural and thermodynamic basis of hydrophobic stabilization in proteins, all of the bulky non-polar residues that are buried or largely buried within the core of T4 lysozyme were substituted with alanine. In 25 cases, including eight reported previously, it was possible to determine the crystal structures of the variants. The structures of four variants with double substitutions were also determined. In the majority of cases the "large-to-small" substitutions lead to internal cavities. In other cases declivities or channels open to the surface were formed. In some cases the structural changes were minimal (mainchain shifts &lt; or = 0.3 A); in other cases mainchain atoms moved up to 2 A. In the case of Ile 29 --&gt; Ala the structure collapsed to such a degree that the volume of the putative cavity was zero. Crystallographic analysis suggests that the occupancy of the engineered cavities by solvent is usually low. The mutants Val 149 --&gt; Ala (V149A) and Met 6 --&gt; Ala (M6A), however, are exceptions and have, respectively, one and two well-ordered water molecules within the cavity. The Val 149 --&gt; Ala substitution allows the solvent molecule to hydrogen bond to polar atoms that are occluded in the wild-type molecule. Similarly, the replacement of Met 6 with alanine allows the two solvent molecules to hydrogen bond to each other and to polar atoms on the protein. Except for Val 149 --&gt; Ala the loss of stability of all the cavity mutants can be rationalized as a combination of two terms. The first is a constant for a given class of substitution (e.g., -2.1 kcal/mol for all Leu --&gt; Ala substitutions) and can be considered as the difference between the free energy of transfer of leucine and alanine from solvent to the core of the protein. The second term can be considered as the energy cost of forming the cavity and is consistent with a numerical value of 22 cal mol(-1) A(-3). Physically, this term is due to the loss of van der Waal's interactions between the bulky sidechain that is removed and the atoms that form the wall of the cavity. The overall results are consistent with the prior rationalization of Leu --&gt; Ala mutants in T4 lysozyme by Eriksson et al. (Eriksson et al., 1992, Science 255:178-183).

The response of T4 lysozyme to large-to-small substitutions within the core and its relation to the hydrophobic effect.,Xu J, Baase WA, Baldwin E, Matthews BW Protein Sci. 1998 Jan;7(1):158-77. PMID:9514271<ref>PMID:9514271</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Lysozyme 3D structures|Lysozyme 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Enterobacteria phage t4]]
[[Category: Lysozyme]]
[[Category: Baase, W A.]]
[[Category: Baldwin, E.]]
[[Category: Matthews, B W.]]
[[Category: Xu, J.]]
[[Category: Bacteriolytic enzyme]]
[[Category: Glycosidase]]
[[Category: Hydrolase]]
[[Category: O-glycosyl]]