1N08: Crystal Structure Of Schizosaccharomyces Pombe Riboflavin Kinase Reveals A Novel Atp And Riboflavin Binding Fold

Citation:
Abstract
The essential redox cofactors riboflavin monophosphate (FMN) and flavin adenine dinucleotide (FAD) are synthesised from their precursor, riboflavin, in sequential reactions by the metal-dependent riboflavin kinase and FAD synthetase. Here, we describe the 1.6A crystal structure of the Schizosaccharomyces pombe riboflavin kinase. The enzyme represents a novel family of phosphoryl transferring enzymes. It is a monomer comprising a central beta-barrel clasped on one side by two C-terminal helices that display an L-like shape. The opposite side of the beta-barrel serves as a platform for substrate binding as demonstrated by complexes with ADP and FMN. Formation of the ATP-binding site requires significant rearrangements in a short alpha-helix as compared to the substrate free form. The diphosphate moiety of ADP is covered by the glycine-rich flap I formed from parts of this alpha-helix. In contrast, no significant changes are observed upon binding of riboflavin. The ribityl side-chain might be covered by a rather flexible flap II. The unusual metal-binding site involves, in addition to the ADP phosphates, only the strictly conserved Thr45. This may explain the preference for zinc observed in vitro.
PDB ID: 1N08Download
MMDB ID: 22070
PDB Deposition Date: 2002/10/11
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.6  Å
Source Organism:
Similar Structures:
Biological Unit for 1N08: monomeric; determined by author
Molecular Components in 1N08
Label Count Molecule
Protein (1 molecule)
1
Putative Riboflavin Kinase(Gene symbol: fmn1)
Molecule annotation
Chemicals (2 molecules)
1
1
2
1
* Click molecule labels to explore molecular sequence information.

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