4OO2: Streptomyces globisporus C-1027 FAD dependent (S)-3-chloro-β-tyrosine-S-SgcC2 C-5 hydroxylase SgcC apo form

C-1027 is a chromoprotein enediyne antitumor antibiotic produced by Streptomyces globisporus. In the last step of biosynthesis of the (S)-3-chloro-5-hydroxy-beta-tyrosine moiety of the C-1027 enediyne chromophore, SgcE6 and SgcC compose a two-component monooxygenase that hydroxylates the C-5 position of (S)-3-chloro-beta-tyrosine. This two-component monooxygenase is remarkable for two reasons. (i) SgcE6 specifically reacts with FAD and NADH, and (ii) SgcC is active with only the peptidyl carrier protein (PCP)-tethered substrate. To address the molecular details of substrate specificity, we determined the crystal structures of SgcE6 and SgcC at 1.66 and 2.63 A resolution, respectively. SgcE6 shares a similar beta-barrel fold with the class I HpaC-like flavin reductases. A flexible loop near the active site of SgcE6 plays a role in FAD binding, likely by providing sufficient space to accommodate the AMP moiety of FAD, when compared to that of FMN-utilizing homologues. SgcC shows structural similarity to a few other known FADH2-dependent monooxygenases and sheds light on some biochemically but not structurally characterized homologues. The crystal structures reported here provide insights into substrate specificity, and comparison with homologues provides a catalytic mechanism of the two-component, FADH2-dependent monooxygenase (SgcE6 and SgcC) that catalyzes the hydroxylation of a PCP-tethered substrate.
PDB ID: 4OO2Download
MMDB ID: 117553
PDB Deposition Date: 2014/1/29
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 2.63  Å
Source Organism:
Similar Structures:
Biological Unit for 4OO2: tetrameric; determined by author and by software (PISA)
Molecular Components in 4OO2
Label Count Molecule
Proteins (4 molecules)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

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