4EIP: Native And K252c Bound Rebc-10x

The indolocarbazole biosynthetic enzymes StaC, InkE, RebC, and AtmC mediate the degree of oxidation of chromopyrrolic acid on route to the natural products staurosporine, K252a, rebeccamycin, and AT2433-A1, respectively. Here, we show that StaC and InkE, which mediate a net 4-electron oxidation, bind FAD with a micromolar K(d), whereas RebC and AtmC, which mediate a net 8-electron oxidation, bind FAD with a nanomolar K(d) while displaying the same FAD redox properties. We further create RebC-10x, a RebC protein with ten StaC-like amino acid substitutions outside of previously characterized FAD-binding motifs and the complementary StaC-10x. We find that these mutations mediate both FAD affinity and product specificity, with RebC-10x displaying higher StaC activity than StaC itself. X-ray structures of this StaC catalyst identify the substrate of StaC as 7-carboxy-K252c and suggest a unique mechanism for this FAD-dependent enzyme.
PDB ID: 4EIPDownload
MMDB ID: 101870
PDB Deposition Date: 2012/4/5
Updated in MMDB: 2012/08
Experimental Method:
x-ray diffraction
Resolution: 2.33  Å
Source Organism:
Similar Structures:
Biological Unit for 4EIP: monomeric; determined by author and by software (PISA)
Molecular Components in 4EIP
Label Count Molecule
Protein (1 molecule)
Putative Fad-monooxygenase
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

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