View source for 1lz4


==ENTHALPIC DESTABILIZATION OF A MUTANT HUMAN LYSOZYME LACKING A DISULFIDE BRIDGE BETWEEN CYSTEINE-77 AND CYSTEINE-95==
<StructureSection load='1lz4' size='340' side='right'caption='[[1lz4]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1lz4]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LZ4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1LZ4 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]] 1.8&#8491;</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=1lz4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1lz4 OCA], [https://pdbe.org/1lz4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1lz4 RCSB], [https://www.ebi.ac.uk/pdbsum/1lz4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1lz4 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/LYSC_HUMAN LYSC_HUMAN] Defects in LYZ are a cause of amyloidosis type 8 (AMYL8) [MIM:[https://omim.org/entry/105200 105200]; also known as systemic non-neuropathic amyloidosis or Ostertag-type amyloidosis. AMYL8 is a hereditary generalized amyloidosis due to deposition of apolipoprotein A1, fibrinogen and lysozyme amyloids. Viscera are particularly affected. There is no involvement of the nervous system. Clinical features include renal amyloidosis resulting in nephrotic syndrome, arterial hypertension, hepatosplenomegaly, cholestasis, petechial skin rash.<ref>PMID:8464497</ref> 
== Function ==
[https://www.uniprot.org/uniprot/LYSC_HUMAN LYSC_HUMAN] Lysozymes have primarily a bacteriolytic function; those in tissues and body fluids are associated with the monocyte-macrophage system and enhance the activity of immunoagents.
== 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/lz/1lz4_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1lz4 ConSurf].
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== Publication Abstract from PubMed ==
To understand the role of disulfide bridges in protein stability, the thermodynamic changes in the denaturation of two mutant human lysozymes lacking a disulfide bridge between Cys-77 and Cys-95 (C77A and C77/95A) were analyzed using differential scanning calorimetry (DSC). At pH 3.0 and 57 degrees C, the stabilities of both the C77A and C77/95A mutants were decreased about 4.6 kcal.mol-1 in Gibbs free energy change. Under the same conditions, the enthalpy changes (delta H) were 94.8 and 90.8 kcal.mol-1, respectively, which were smaller than that of the wild type (100.8 kcal.mol-1). The destabilization of the mutants was caused by enthalpic factors. Although X-ray crystallography indicated that the mutants preserve the wild-type tertiary structure, removal of the disulfide bridge increased the flexibility of the native state of the mutants. This was indicated both by an increase in the crystallographic thermal factors (B-factors) and by a decrease in the affinity of N-acetylglucosamine trimer [(NAG)3] observed using isothermal titration calorimetry (DTC) due to entropic effects. Thus, the effect of cross-linking on the stability of a protein is not solely explained by the entropy change in denaturation.

Enthalpic destabilization of a mutant human lysozyme lacking a disulfide bridge between cysteine-77 and cysteine-95.,Kuroki R, Inaka K, Taniyama Y, Kidokoro S, Matsushima M, Kikuchi M, Yutani K Biochemistry. 1992 Sep 8;31(35):8323-8. PMID:1525170<ref>PMID:1525170</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1lz4" style="background-color:#fffaf0;"></div>

==See Also==
*[[Lysozyme 3D structures|Lysozyme 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Inaka K]]
[[Category: Kikuchi M]]
[[Category: Kuroki R]]
[[Category: Matsushima M]]
[[Category: Taniyama Y]]