2OG5

Crystal structure of asparagine oxygenase (AsnO)

Summary for 2OG5

• Entry DOI: 10.2210/pdb2og5/pdb
• Descriptor: Putative oxygenase, SODIUM ION, ACETIC ACID, ... (4 entities in total)
• Functional Keywords: non-ribosomal peptide synthesis, iron(ii)/alpha-ketoglutarate dependent hydroxylase, jelly-roll fold, beta-hydroxylation of amino acids, oxidoreductase
• Biological source: Streptomyces coelicolor
• Total number of polymer chains: 1
• Total formula weight: 39032.62

Authors

Essen, L.O.,Strieker, M. (deposition date: 2007-01-05, release date: 2007-03-06, Last modification date: 2023-08-30)

Primary citation

Strieker, M.,Kopp, F.,Mahlert, C.,Essen, L.O.,Marahiel, M.A.
Mechanistic and structural basis of stereospecific Cbeta-hydroxylation in calcium-dependent antibiotic, a daptomycin-type lipopeptide.
Acs Chem.Biol., 2:187-196, 2007

PubMed Abstract: Non-ribosomally synthesized lipopeptide antibiotics of the daptomycin type are known to contain unnatural beta-modified amino acids, which are essential for bioactivity. Here we present the biochemical and structural basis for the incorporation of 3-hydroxyasparagine at position 9 in the 11-residue acidic lipopeptide lactone calcium-dependent antibiotic (CDA). Direct hydroxylation of l-asparagine by AsnO, a non-heme Fe(2+)/alpha-ketoglutarate-dependent oxygenase encoded by the CDA biosynthesis gene cluster, was validated by Fmoc derivatization of the reaction product and LC/MS analysis. The 1.45, 1.92, and 1.66 A crystal structures of AsnO as apoprotein, Fe(2+) complex, and product complex, respectively, with (2S,3S)-3-hydroxyasparagine and succinate revealed the stereoselectivity and substrate specificity of AsnO. The comparison of native and product-complex structures of AsnO showed a lid-like region (residues F208-E223) that seals the active site upon substrate binding and shields it from sterically demanding peptide substrates. Accordingly, beta-hydroxylated asparagine is synthesized prior to its incorporation into the growing CDA peptide. The AsnO structure could serve as a template for engineering novel enzymes for the synthesis of beta-hydroxylated amino acids.

PubMed: 17373765
DOI: 10.1021/cb700012y

Experimental method

X-RAY DIFFRACTION (1.45 Å)