2jer: Difference between revisions
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==Overview== | ==Overview== | ||
Enterococcus faecalis makes ATP from agmatine in three steps catalyzed by, agmatine deiminase (AgDI), putrescine transcarbamylase (PTC), and, carbamate kinase (CK). An antiporter exchanges putrescine for agmatine. We, have cloned the E. faecalis ef0732 and ef0734 genes of the reported gene, cluster for agmatine catabolism, overexpressed them in Escherichia coli, purified the products, characterized them functionally as PTC and AgDI, and crystallized and X-ray diffracted them. The 1.65-Angstroms-resolution, structure of AgDI forming a covalent adduct with an agmatine-derived, amidine reactional intermediate is described. We provide definitive, identification of the gene cluster for agmatine catabolism and confirm, that ornithine is a genuine but poor PTC substrate, suggesting that PTC, ... | Enterococcus faecalis makes ATP from agmatine in three steps catalyzed by, agmatine deiminase (AgDI), putrescine transcarbamylase (PTC), and, carbamate kinase (CK). An antiporter exchanges putrescine for agmatine. We, have cloned the E. faecalis ef0732 and ef0734 genes of the reported gene, cluster for agmatine catabolism, overexpressed them in Escherichia coli, purified the products, characterized them functionally as PTC and AgDI, and crystallized and X-ray diffracted them. The 1.65-Angstroms-resolution, structure of AgDI forming a covalent adduct with an agmatine-derived, amidine reactional intermediate is described. We provide definitive, identification of the gene cluster for agmatine catabolism and confirm, that ornithine is a genuine but poor PTC substrate, suggesting that PTC, (found here to be trimeric) evolved from ornithine transcarbamylase., N-(Phosphonoacetyl)-putrescine was prepared and shown to strongly (K(i) =, 10 nM) and selectively inhibit PTC and to improve PTC crystallization. We, find that E. faecalis AgDI, which is committed to ATP generation, closely, resembles the AgDIs involved in making polyamines, suggesting the, recruitment of a polyamine-synthesizing AgDI into the AgDI pathway. The, arginine deiminase (ADI) pathway of arginine catabolism probably supplied, the genes for PTC and CK but not those for the agmatine/putrescine, antiporter, and thus the AgDI and ADI pathways are not related by a single, "en bloc" duplication event. The AgDI crystal structure reveals a tetramer, with a five-blade propeller subunit fold, proves that AgDI closely, resembles ADI despite a lack of sequence identity, and explains substrate, affinity, selectivity, and Cys357-mediated-covalent catalysis. A, three-tongued agmatine-triggered gating opens or blocks access to the, active center. | ||
==About this Structure== | ==About this Structure== | ||
2JER is a | 2JER is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Enterococcus_faecalis Enterococcus faecalis] with AGT and AGT as [http://en.wikipedia.org/wiki/ligands ligands]. This structure superseeds the now removed PDB entry 2J2T. Active as [http://en.wikipedia.org/wiki/Agmatine_deiminase Agmatine deiminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.3.12 3.5.3.12] Structure known Active Site: CATALYTIC. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2JER OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: tetramer]] | [[Category: tetramer]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:02:47 2007'' | ||
