View source for 2f9o

[[Image:2f9o.gif|left|200px]]<br />
<applet load="2f9o" size="450" color="white" frame="true" align="right" spinBox="true" 
caption="2f9o, resolution 2.10&Aring;" />
'''Crystal Structure of the Recombinant Human Alpha I Tryptase Mutant D216G'''<br />

==Overview==
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.

==About this Structure==
2F9O is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Active as [http://en.wikipedia.org/wiki/Tryptase Tryptase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.59 3.4.21.59] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2F9O OCA]. 

==Reference==
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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16414069 16414069]
[[Category: Homo sapiens]]
[[Category: Single protein]]
[[Category: Tryptase]]
[[Category: Bode, W.]]
[[Category: Huber, R.]]
[[Category: Marquardt, U.]]
[[Category: Rohr, K.B.]]
[[Category: Schechter, N.M.]]
[[Category: Selwood, T.]]
[[Category: Than, M.E.]]
[[Category: difucosylation]]
[[Category: serine proteinase]]
[[Category: trypsin-like]]

''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 12 22:02:06 2007''