2g68
From Proteopedia
(New page: 200px<br /><applet load="2g68" size="450" color="white" frame="true" align="right" spinBox="true" caption="2g68, resolution 2.50Å" /> '''Crystal structure of...) |
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caption="2g68, resolution 2.50Å" /> | caption="2g68, resolution 2.50Å" /> | ||
'''Crystal structure of X. campestris N-acetylornithine transcarbamylase E92P mutant complexed with carbamoyl phosphate and N-succinylnorvaline'''<br /> | '''Crystal structure of X. campestris N-acetylornithine transcarbamylase E92P mutant complexed with carbamoyl phosphate and N-succinylnorvaline'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 2G68 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Xanthomonas_campestris_pv._campestris Xanthomonas campestris pv. campestris] with SO4, SN0 and CP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/N-acetylornithine_carbamoyltransferase N-acetylornithine carbamoyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.3.9 2.1.3.9] Full crystallographic information is available from [http:// | + | 2G68 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Xanthomonas_campestris_pv._campestris Xanthomonas campestris pv. campestris] with <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=SN0:'>SN0</scene> and <scene name='pdbligand=CP:'>CP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/N-acetylornithine_carbamoyltransferase N-acetylornithine carbamoyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.3.9 2.1.3.9] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G68 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
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Revision as of 10:02, 23 January 2008
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Crystal structure of X. campestris N-acetylornithine transcarbamylase E92P mutant complexed with carbamoyl phosphate and N-succinylnorvaline
Overview
Transcarbamylases catalyze the transfer of the carbamyl group from, carbamyl phosphate (CP) to an amino group of a second substrate such as, aspartate, ornithine, or putrescine. Previously, structural determination, of a transcarbamylase from Xanthomonas campestris led to the discovery of, a novel N-acetylornithine transcarbamylase (AOTCase) that catalyzes the, carbamylation of N-acetylornithine. Recently, a novel N-succinylornithine, transcarbamylase (SOTCase) from Bacteroides fragilis was identified., Structural comparisons of AOTCase from X. campestris and SOTCase from B., fragilis revealed that residue Glu92 (X. campestris numbering) plays a, critical role in distinguishing AOTCase from SOTCase. Enzymatic assays of, E92P, E92S, E92V, and E92A mutants of AOTCase demonstrate that each of, these mutations converts the AOTCase to an SOTCase. Similarly, the P90E, mutation in B. fragilis SOTCase (equivalent to E92 in X. campestris, AOTCase) converts the SOTCase to AOTCase. Hence, a single amino acid, substitution is sufficient to swap the substrate specificities of AOTCase, and SOTCase. X-ray crystal structures of these mutants in complexes with, CP and N-acetyl-L-norvaline (an analog of N-acetyl-L-ornithine) or, N-succinyl-L-norvaline (an analog of N-succinyl-L-ornithine) substantiate, this conversion. In addition to Glu92 (X. campestris numbering), other, residues such as Asn185 and Lys30 in AOTCase, which are involved in, binding substrates through bridging water molecules, help to define the, substrate specificity of AOTCase. These results provide the correct, annotation (AOTCase or SOTCase) for a set of the transcarbamylase-like, proteins that have been erroneously annotated as ornithine, transcarbamylase (OTCase, EC 2.1.3.3).
About this Structure
2G68 is a Single protein structure of sequence from Xanthomonas campestris pv. campestris with , and as ligands. Active as N-acetylornithine carbamoyltransferase, with EC number 2.1.3.9 Full crystallographic information is available from OCA.
Reference
A single mutation in the active site swaps the substrate specificity of N-acetyl-L-ornithine transcarbamylase and N-succinyl-L-ornithine transcarbamylase., Shi D, Yu X, Cabrera-Luque J, Chen TY, Roth L, Morizono H, Allewell NM, Tuchman M, Protein Sci. 2007 Aug;16(8):1689-99. Epub 2007 Jun 28. PMID:17600144
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