1a1s

<table><tr><td colspan='2'>[[1a1s]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A1S OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1A1S FirstGlance]. <br>

</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Ornithine_carbamoyltransferase Ornithine carbamoyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.3.3 2.1.3.3] </span></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=1a1s FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1a1s OCA], [http://pdbe.org/1a1s PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1a1s RCSB], [http://www.ebi.ac.uk/pdbsum/1a1s PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1a1s ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/OTC_PYRFU OTC_PYRFU]] Reversibly catalyzes the transfer of the carbamoyl group from carbamoyl phosphate (CP) to the N(epsilon) atom of ornithine (ORN) to produce L-citrulline, which is a substrate for argininosuccinate synthetase, the enzyme involved in the final step in arginine biosynthesis.<ref>PMID:9288930</ref>

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== Publication Abstract from PubMed ==

The Pyrococcus furiosus (PF) ornithine carbamoyltransferase (OTCase; EC 2.1.3.3) is an extremely heat-stable enzyme that maintains about 50% of its activity after heat treatment for 60 min at 100 degrees C. To understand the molecular basis of thermostability of this enzyme, we have determined its three-dimensional structure at a resolution of 2.7 A and compared it with the previously reported structures of OTCases isolated from mesophilic bacteria. Most OTCases investigated up to now are homotrimeric and devoid of allosteric properties. A striking exception is the catabolic OTCase from Pseudomonas aeruginosa, which is allosterically regulated and built up of four trimers disposed in a tetrahedral manner, an architecture that actually underlies the allostery of the enzyme. We now report that the thermostable PF OTCase (420 kDa) presents the same 23-point group symmetry. The enzyme displays Michaelis-Menten kinetics. A detailed comparison of the two enzymes suggests that, in OTCases, not only allostery but also thermophily was achieved through oligomerization of a trimer as a common catalytic motif. Thermal stabilization of the PF OTCase dodecamer is mainly the result of hydrophobic interfaces between trimers, at positions where allosteric binding sites have been identified in the allosteric enzyme. The present crystallographic analysis of PF OTCase provides a structural illustration that oligomerization can play a major role in extreme thermal stabilization.

The crystal structure of Pyrococcus furiosus ornithine carbamoyltransferase reveals a key role for oligomerization in enzyme stability at extremely high temperatures.,Villeret V, Clantin B, Tricot C, Legrain C, Roovers M, Stalon V, Glansdorff N, Van Beeumen J Proc Natl Acad Sci U S A. 1998 Mar 17;95(6):2801-6. PMID:9501170<ref>PMID:9501170</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 1a1s" style="background-color:#fffaf0;"></div>

*[[Ornithine carbamoyltransferase|Ornithine carbamoyltransferase]]

[[Category: Ornithine carbamoyltransferase]]

[[Category: Beeumen, J Van]]

[[Category: Clantin, B]]

[[Category: Glansdorff, N]]

[[Category: Legrain, C]]

[[Category: Roovers, M]]

[[Category: Stalon, V]]

[[Category: Tricot, C]]

[[Category: Villeret, V]]

[[Category: Transcarbamylase]]