View source for 1nuf


==Role of Calcium Ions in the Activation and Activity of the Transglutaminase 3 Enzyme==
<StructureSection load='1nuf' size='340' side='right'caption='[[1nuf]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1nuf]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NUF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NUF FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BR:BROMIDE+ION'>BR</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1l9m|1l9m]], [[1l9n|1l9n]], [[1nud|1nud]], [[1nug|1nug]]</div></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">TGM3 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Protein-glutamine_gamma-glutamyltransferase Protein-glutamine gamma-glutamyltransferase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.2.13 2.3.2.13] </span></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=1nuf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1nuf OCA], [https://pdbe.org/1nuf PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1nuf RCSB], [https://www.ebi.ac.uk/pdbsum/1nuf PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1nuf ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/TGM3_HUMAN TGM3_HUMAN]] Catalyzes the calcium-dependent formation of isopeptide cross-links between glutamine and lysine residues in various proteins, as well as the conjugation of polyamines to proteins. Involved in the formation of the cornified envelope (CE), a specialized component consisting of covalent cross-links of proteins beneath the plasma membrane of terminally differentiated keratinocytes. Catalyzes small proline-rich proteins (SPRR1 and SPRR2) and LOR cross-linking to form small interchain oligomers, which are further cross-linked by TGM1 onto the growing CE scaffold (By similarity). In hair follicles, involved in cross-linking structural proteins to hardening the inner root sheath. 
== 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/nu/1nuf_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=1nuf ConSurf].
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== Publication Abstract from PubMed ==
The transglutaminase 3 enzyme is widely expressed in many tissues including epithelia. We have shown previously that it can bind three Ca2+ ions, which in site one is constitutively bound, while those in sites two and three are acquired during activation and are required for activity. In particular, binding at site three opens a channel through the enzyme and exposes two tryptophan residues near the active site that are thought to be important for enzyme reaction. In this study, we have solved the structures of three more forms of this enzyme by x-ray crystallography in the presence of Ca2+ and/or Mg2+, which provide new insights on the precise contribution of each Ca2+ ion to activation and activity. First, we found that Ca2+ ion in site one can be exchanged with difficulty, and it has a binding affinity of Kd = 0.3 microm (DeltaH = -6.70 +/- 0.52 kcal/mol), which suggests it is important for the stabilization of the enzyme. Site two can be occupied by some lanthanides but only Ca2+ of the Group 2 family of alkali earth metals, and its occupancy are required for activity. Site three can be occupied by some lanthanides, Ca2+,or Mg2+; however, when Mg2+ is present, the enzyme is inactive, and the channel is closed. Thus Ca2+ binding in both sites two and three cooperate in opening the channel. We speculate that manipulation of the channel opening could be controlled by intracellular cation levels. Together, these data have important implications for reaction mechanism of the enzyme: the opening of a channel perhaps controls access to and manipulation of substrates at the active site.

Roles of calcium ions in the activation and activity of the transglutaminase 3 enzyme.,Ahvazi B, Boeshans KM, Idler W, Baxa U, Steinert PM J Biol Chem. 2003 Jun 27;278(26):23834-41. Epub 2003 Apr 4. PMID:12679341<ref>PMID:12679341</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Protein-glutamine gamma-glutamyltransferase]]
[[Category: Ahvazi, B]]
[[Category: Calcium ion]]
[[Category: Metalloenzyme]]
[[Category: Transferase]]
[[Category: Transglutaminase 3]]