2bln: Difference between revisions
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==Overview== | ==Overview== | ||
Modification of the lipid A moiety of lipopolysaccharide by the addition, of the sugar 4-amino-4-deoxy-L-arabinose (L-Ara4N) is a strategy adopted, by pathogenic Gram-negative bacteria to evade cationic antimicrobial, peptides produced by the innate immune system. L-Ara4N biosynthesis is, therefore a potential anti-infective target, because inhibiting its, synthesis would render certain pathogens more sensitive to the immune, system. The bifunctional enzyme ArnA, which is required for L-Ara4N, biosynthesis, catalyzes the NAD(+)-dependent oxidative decarboxylation of, UDP-glucuronic acid to generate a UDP-4'-keto-pentose sugar and also, catalyzes transfer of a formyl group from N-10-formyltetrahydrofolate to, the 4'-amine of UDP-L-Ara4N. We now report the crystal structure of the, ... | Modification of the lipid A moiety of lipopolysaccharide by the addition, of the sugar 4-amino-4-deoxy-L-arabinose (L-Ara4N) is a strategy adopted, by pathogenic Gram-negative bacteria to evade cationic antimicrobial, peptides produced by the innate immune system. L-Ara4N biosynthesis is, therefore a potential anti-infective target, because inhibiting its, synthesis would render certain pathogens more sensitive to the immune, system. The bifunctional enzyme ArnA, which is required for L-Ara4N, biosynthesis, catalyzes the NAD(+)-dependent oxidative decarboxylation of, UDP-glucuronic acid to generate a UDP-4'-keto-pentose sugar and also, catalyzes transfer of a formyl group from N-10-formyltetrahydrofolate to, the 4'-amine of UDP-L-Ara4N. We now report the crystal structure of the, N-terminal formyltransferase domain in a complex with uridine, monophosphate and N-5-formyltetrahydrofolate. Using this structure, we, identify the active site of formyltransfer in ArnA, including the key, catalytic residues Asn(102), His(104), and Asp(140). Additionally, we have, shown that residues Ser(433) and Glu(434) of the decarboxylase domain are, required for the oxidative decarboxylation of UDP-GlcUA. An E434Q mutant, is inactive, suggesting that chemical rather than steric properties of, this residue are crucial in the decarboxylation reaction. Our data suggest, that the decarboxylase domain catalyzes both hydride abstraction, (oxidation) from the C-4' position and the subsequent decarboxylation. | ||
==About this Structure== | ==About this Structure== | ||
2BLN is a | 2BLN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with ACT, FON and U5P as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Guanidinoacetate_N-methyltransferase Guanidinoacetate N-methyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.2 2.1.1.2] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BLN OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
''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 15:02:22 2007'' | ||
