2qce: Difference between revisions

From Proteopedia
Jump to navigationJump to search
OCA (talk | contribs)
No edit summary
OCA (talk | contribs)
No edit summary
Line 4: Line 4:


==Overview==
==Overview==
UMP synthase (UMPS) catalyzes the last two steps of de novo pyrimidine, nucleotide synthesis and is a potential cancer drug target. The C-terminal, domain of UMPS is orotidine-5'-monophosphate decarboxylase (OMPD), a, cofactor-less yet extremely efficient enzyme. Studies of OMPDs from, micro-organisms led to the proposal of several noncovalent decarboxylation, mechanisms via high-energy intermediates. We describe nine crystal, structures of human OMPD in complex with substrate, product, and, nucleotide inhibitors. Unexpectedly, simple compounds can replace the, natural nucleotides and induce a closed conformation of OMPD, defining a, tripartite catalytic site. The structures outline the requirements drugs, must meet to maximize therapeutic effects and minimize cross-species, activity. Chemical mimicry by iodide identified a CO(2) product binding, site. Plasticity of catalytic residues and a covalent OMPD-UMP complex, prompt a reevaluation of the prevailing decarboxylation mechanism in favor, of covalent intermediates. This mechanism can also explain the observed, catalytic promiscuity of OMPD.
UMP synthase (UMPS) catalyzes the last two steps of de novo pyrimidine nucleotide synthesis and is a potential cancer drug target. The C-terminal domain of UMPS is orotidine-5'-monophosphate decarboxylase (OMPD), a cofactor-less yet extremely efficient enzyme. Studies of OMPDs from micro-organisms led to the proposal of several noncovalent decarboxylation mechanisms via high-energy intermediates. We describe nine crystal structures of human OMPD in complex with substrate, product, and nucleotide inhibitors. Unexpectedly, simple compounds can replace the natural nucleotides and induce a closed conformation of OMPD, defining a tripartite catalytic site. The structures outline the requirements drugs must meet to maximize therapeutic effects and minimize cross-species activity. Chemical mimicry by iodide identified a CO(2) product binding site. Plasticity of catalytic residues and a covalent OMPD-UMP complex prompt a reevaluation of the prevailing decarboxylation mechanism in favor of covalent intermediates. This mechanism can also explain the observed catalytic promiscuity of OMPD.


==Disease==
==Disease==
Line 28: Line 28:
[[Category: ump synthase]]
[[Category: ump synthase]]


''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Feb 13 08:18:18 2008''
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:38:05 2008''