==Crystal Structure of the Recombinant Human Alpha I Tryptase Mutant D216G in Complex with Leupeptin==

<StructureSection load='2f9p' size='340' side='right' caption='[[2f9p]], [[Resolution|resolution]] 2.30&Aring;' scene=''>

<table><tr><td colspan='2'>[[2f9p]] is a 8 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2F9P OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2F9P FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BU3:(R,R)-2,3-BUTANEDIOL'>BU3</scene>, <scene name='pdbligand=FUC:ALPHA-L-FUCOSE'>FUC</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2f9p FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2f9p OCA], [http://pdbe.org/2f9p PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2f9p RCSB], [http://www.ebi.ac.uk/pdbsum/2f9p PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2f9p ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

Tryptases alpha and beta are trypsin-like serine proteinases expressed in large amounts by mast cells. Beta-tryptase is a tetramer that has enzymatic activity, but requires heparin binding to maintain functional and structural stability, whereas alpha-tryptase has little, if any, enzymatic activity but is a stable tetramer in the absence of heparin. As shown previously, these differences can be mainly attributed to the different conformations of the 214-220 segment. Interestingly, the replacement of Asp216 by Gly, which is present in beta-tryptase, results in enzymatically active but less stable alpha-tryptase mutants. We have solved the crystal structures of both the single (D216G) and the double (K192Q/D216G) mutant forms of recombinant human alphaI-tryptase in complex with the peptide inhibitor leupeptin, as well as the structure of the non-inhibited single mutant. The inhibited mutants exhibited an open functional substrate binding site, while in the absence of an inhibitor, the open (beta-tryptase-like) and the closed (alpha-tryptase-like) conformations were present simultaneously. This shows that both forms are in a two-state equilibrium, which is influenced by the residues in the vicinity of the active site and by inhibitor/substrate binding. Novel insights regarding the observed stability differences as well as a potential proteolytic activity of wild-type alpha-tryptase, which may possess a cryptic active site, are discussed.

X-ray structures of free and leupeptin-complexed human alphaI-tryptase mutants: indication for an alpha--&gt;beta-tryptase transition.,Rohr KB, Selwood T, Marquardt U, Huber R, Schechter NM, Bode W, Than ME J Mol Biol. 2006 Mar 17;357(1):195-209. Epub 2005 Dec 28. PMID:16414069<ref>PMID:16414069</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 2f9p" style="background-color:#fffaf0;"></div>

==See Also==

*[[Tryptase|Tryptase]]

== References ==

<references/>

[[Category: Human]]

[[Category: Tryptase]]

[[Category: Trypsin-like]]