1l9n: Difference between revisions

Revision as of 23:42, 2 May 2008

Three-dimensional structure of the human transglutaminase 3 enzyme: binding of calcium ions change structure for activation

OverviewOverview

Transglutaminase (TGase) enzymes catalyze the formation of covalent cross-links between protein-bound glutamines and lysines in a calcium-dependent manner, but the role of Ca(2+) ions remains unclear. The TGase 3 isoform is widely expressed and is important for epithelial barrier formation. It is a zymogen, requiring proteolysis for activity. We have solved the three-dimensional structures of the zymogen and the activated forms at 2.2 and 2.1 A resolution, respectively, and examined the role of Ca(2+) ions. The zymogen binds one ion tightly that cannot be exchanged. Upon proteolysis, the enzyme exothermally acquires two more Ca(2+) ions that activate the enzyme, are exchangeable and are functionally replaceable by other lanthanide trivalent cations. Binding of a Ca(2+) ion at one of these sites opens a channel which exposes the key Trp236 and Trp327 residues that control substrate access to the active site. Together, these biochemical and structural data reveal for the first time in a TGase enzyme that Ca(2+) ions induce structural changes which at least in part dictate activity and, moreover, may confer substrate specificity.

About this StructureAbout this Structure

1L9N is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

ReferenceReference

Three-dimensional structure of the human transglutaminase 3 enzyme: binding of calcium ions changes structure for activation., Ahvazi B, Kim HC, Kee SH, Nemes Z, Steinert PM, EMBO J. 2002 May 1;21(9):2055-67. PMID:11980702 Page seeded by OCA on Fri May 2 23:42:07 2008

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OCA

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 [[Image:1l9n.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1l9n |SIZE=350|CAPTION= <scene name='initialview01'>1l9n</scene>, resolution 2.10&Aring;
+The line below this paragraph, containing "STRUCTURE_1l9n", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=BGL:B-2-OCTYLGLUCOSIDE'>BGL</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Protein-glutamine_gamma-glutamyltransferase Protein-glutamine gamma-glutamyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.2.13 2.3.2.13] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE= TGM3 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])
+-->
-|DOMAIN=
+{{STRUCTURE_1l9n|  PDB=1l9n  |  SCENE=  }}
-|RELATEDENTRY=[[1l9m|1L9M]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1l9n FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1l9n OCA], [http://www.ebi.ac.uk/pdbsum/1l9n PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1l9n RCSB]</span>
-}}
 '''Three-dimensional structure of the human transglutaminase 3 enzyme: binding of calcium ions change structure for activation'''
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 [[Category: Single protein]]
 [[Category: Ahvazi, B.]]
-[[Category: activation]]
+[[Category: Activation]]
-[[Category: calcium binding]]
+[[Category: Calcium binding]]
-[[Category: transglutaminase]]
+[[Category: Transglutaminase]]
-[[Category: x-ray structure]]
+[[Category: X-ray structure]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 23:42:07 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 22:00:00 2008''