5FO1: E301a Mutant Of Fad Synthetase From Corynebacterium Ammoniagenes

Bifunctional FAD synthetases (FADSs) fold in two independent modules; The C-terminal riboflavin kinase (RFK) catalyzes the RFK activity, while the N-terminal FMN-adenylyltransferase (FMNAT) exhibits the FMNAT activity. The search for macromolecular interfaces in the Corynebacterium ammoniagenes FADS (CaFADS) crystal structure predicts a dimer of trimers organization. Within each trimer, a head-to-tail arrangement causes the RFK and FMNAT catalytic sites of the two neighboring protomers to approach, in agreement with active site residues of one module influencing the activity at the other. We analyze the relevance of the CaFADS head-to-tail macromolecular interfaces to stabilization of assemblies, catalysis and ligand binding. With this aim, we evaluate the effect of point mutations in loop L1c-FlapI, loop L6c, and helix alpha1c of the RFK module (positions K202, E203, F206, D298, V300, E301 and L304), regions at the macromolecular interface between two protomers within the trimer. Although none of the studied residues is critical in the formation and dissociation of assemblies, residues at L1c-FlapI and helix alpha1c particularly modulate quaternary architecture, as well as ligand binding and kinetic parameters involved with RFK and FMNAT activities. These data support the influence of transient oligomeric structures on substrate accommodation and catalysis at both CaFADS active sites.
PDB ID: 5FO1Download
MMDB ID: 145223
PDB Deposition Date: 2015/11/17
Updated in MMDB: 2016/12
Experimental Method:
x-ray diffraction
Resolution: 2.45  Å
Source Organism:
Similar Structures:
Biological Unit for 5FO1: hexameric; determined by author and by software (PISA)
Molecular Components in 5FO1
Label Count Molecule
Proteins (6 molecules)
Riboflavin Biosynthesis Protein Ribf
Molecule annotation
Chemicals (12 molecules)
* Click molecule labels to explore molecular sequence information.

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